Decoder Integration Layer (DIL)

Introduction

The DIL (Decoder Integration Layer) is the V-Nova library used to integrate LCEVC decoding and rendering to an existing legacy decoder implementation.

The DIL can be used in both:

• Application integration - the DIL renders directly onto an on-screen surface, provided by the client, of arbitrary size (generally different from the content resolution). Examples: ExoPlayer (Android).

• OS Integration - the DIL decodes onto a buffer or draws onto an off screen texture of the same size of the content final resolution, it doesn’t handle the final render to display, including YUV to RGB conversion, and resizing to the destination surface. Examples: MFT (Windows), OMX (Android).

The following block diagram illustrates the role of the DIL more clearly. In conjunction with a base decoder, typically provided by the OS, it offers a complete solution from buffer to output.

Figure 1 Unmodified and LCEVC Pipeline using the DIL

Functionality

Input & output

As shown in the diagram above, the DIL needs two inputs:

• input buffers - the same buffers that are fed to the base decoder in encoding order;

• base decoded frames - produced by the base decoder in presentation order;

and produces an output onto either a

• buffer or

• offscreen texture or

• onscreen surface.

Colour formats

The DIL can operate on a base decoded picture in the following colour formats:

• YUV420 I420 - planar Y, U and V with 4:2:0 subsampled chroma;

• YUV420 NV12 - semi-planar Y (planar), and UV (interleaved) with 4:2:0 subsampled chroma;

• RGB/RGBA - raster Red Green Blue, i.e. on one plane with interleaved colour components;

Modes

The DIL can be configured to work with two types of internal pipeline:

• CPU - all the LCEVC stages are performed in CPU, only using SIMD acceleration, by means of the DPI only, the GPU is used only for the possible YUV/RGB conversion;

• GPU - most of the LCEVC stages are performed in GPU suing GL shaders, including YUV/RGB conversions, while the CPU is only used to produce the LCEVC residual planes at both LOQs

Output type

The DIL offers decoding to either

• on screen

• off screen

On screen refers to a window from the OS window system, currently EGL and GLFW windowing systems are supported.

Off screen refers to an array of buffers or GL textures in memory. The latter case has been designed to allow the client to manage decode and presentation separately, for example to allow buffering/queuing already decoded pictures before display.

Other configurable features

On creating a DIL instance, the client can configure additional features, such as:

• OpenGL major and minor versions (to force a specific version over the system’s selected one);

• Use of OpenGL ES;

• Use of 8 bit LCEVC residual planes - instead of 16 bit

• Use of Hardware Buffers - (Apple and Android only)

• Enable an on screen UI for stats and live config;

• Enable dumping stats to local storage;

• Enable dumping raw output frames to local storage;

The clients configures the DIL at creation time by passing a JSON string and a pair of window system related parameters for context and destination surface.

API Overview

Using the DIL is fairly easy, especially if compared to the more basic DPI, since it operates at a relatively high abstraction level. Apart from obvious creation and destruction of a DIL instance (respectively DIL_Create() and DIL_Destroy()), the main API calls are effectively two:

• Feed input - DIL_AddNALData()

• Decode - DIL_DecodeandRender() (for decoding on screen, alternatively DIL_Decode() for decoding off screen followed by DIL_Render())

• Feed input - DIL_AddNALData()

• Decode - DIL_DecodeandRender() (for decoding on screen, alternatively DIL_Decode() for decoding off screen followed by DIL_Render())

The DIL also offers an API for the client to retrieve the size of the output picture, which can be useful to pre-allocate buffers or textures of the right size before decoding:

• Get size information - DIL_GetDecodeInformation()

Note: input buffers must have NAL byte stream format with either Annex B or Length Prefix format.

Drop/Skip frames

LCEVC content may be encoded with a temporal feature that requires each and every frame to be actioned on in order to keep the DPI internal temporal reference data correct. As a result when the client skips frames, for ex. because of a seek in the timeline, or drops frames because they are “late”, it shall let the DIL know by calling the following function:

• DIL_DecodeSkip()

The DIL does know whether the temporal feature is on and therefore can fall back to a no operation case if that is the case. It is not advised that the client tries to implement this behaviour on its side.

Synchronous and Asynchronous modes

The DIL can be used in both synchronous or asynchronous mode. This is applicable to the decode and render functions:

• DIL_Decode()

• DIL_DecodeAndRender()

• DIL_DecodeSkip()

• DIL_Render()

If the client has previously set the callback function by means of the DIL_SetDecodedAsyncCallback() or DIL_SetRenderAsyncCallback() API calls, the above decode functions will work asynchronously, therefore returning immediately and triggering the client’s callback function when the decode (or render) has completed. If the callback has not been set the functions will work synchronously.

Base pass-through mode

The DIL also supports a pass-through mode, in which the base is simply copied on to the output without applying the LCEVC enhancement. This mode is triggered when no LCEVC data is found for the frame and can be set as forced behaviour, for every frame, from the JSON configuration.

Example Integration Code

In basic terms, a sample integration code using the DIL can be briefly described, among the various phases, as follows:

// Include DIL header
#include <lcevc_dil.h>
// Initialisation phase ///////////////////////////////////////////////////////
// Create an instance of the DIL
DIL_ContextSettings context_settings = { 0 };
char * json_settings = "{\
 \"gl_decode\": true,\
 \"gl_es\": true,\
 \"gl_major\": 3,\
 \"gl_minor\": 1,\
 \"swap_interval\": 0,\
 \"fullscreen\": false,\
 \"hardware_buffers\": false,\
 \"use_u8_surface\": false,\
 \"force_passthrough\": false\
}";
// Create a DIL instance
DIL_Decoder decoder = nullptr;
if (DIL_Create(json_settings, &context_settings , &decoder) != DIL_RC_Success)
{
    fprintf(stderr, "Unable to create DIL instance\n");
    exit(-1);
}
// Destruction phase //////////////////////////////////////////////////////////
DIL_Destroy(decoder);
decoder = nullptr;
// Handling input buffers /////////////////////////////////////////////////////
//...
DIL_NALFormat nalFormat;
// Set NAL format, from metadata, properties or parsing the input buffers
// ...
if (DIL_AddNALData(decoder, inputCc, presentationTimeStamp, buffer, length, nalFormat) != DIL_RC_Success)
{
    fprintf(stderr, "Unable to pass input buffer for inputCc=%u pts=%PRId64\n", inputCc, presentationTimeStamp);
    exit(-2);
}
// Handling decoded frame from base decoder ///////////////////////////////////
// ...
// Get size of ouput picture if needed
DIL_DecodeInformation decodeInfo;
if (DIL_GetDecodeInformation(decoder, inputCc, presentationTimeStamp, baseWidth, baseHeight, &decodeInfo) != DIL_RC_Success)
{
    fprintf(stderr, "DIL get decode info failed for inputCc=%u pts=%PRId64\n", inputCc, baseImage.pts;
    exit(-3);
}
// Using decode info
// ...
DIL_Image baseImage;
// Fill the base "Image" struct with the data properties of the base frame
// ...
DIL_RenderInformation renderInfo;
// Fill rotation and pixel aspect ratio
// ...
if (DIL_DecodeAndRender(decoder, inputCc, presentationTimeStamp, baseImage, &renderInfo, &decodeInfo) != DIL_RC_Success)
{
    fprintf(stderr, "DIL decode failed for pts=%PRId64\n", baseImage.pts;
    exit(-4);
}
// Decode info reports if LCEVC is available and has been applied
// ...

DIL API

DIL_Create

Create an instance of a DIL Decoder

• json_settings JSON string with initialisation parameters

• context_settings settings from the windowing system

• instance decoder instance created

• return DIL API return code

DIL_ReturnCode DIL_Create( const char*                   json_settings,
                           const DIL_ContextSettings*    context_settings,
                           DIL_Decoder                   instance );

DIL_Destroy

Destroy an instance of a DIL Decoder

• decoder instance to be destroyed

void DIL_Destroy( DIL_Decoder decoder);

DIL_GetImage

Returns a fresh usable instance of DIL_Image

• decoder DIL instance

• image_desc Describing Image configurations

• image Result DIL_Image if creation is successful, NULL otherwise

• return DIL_RC_Error if image_desc contains incompatible values

DIL_ReturnCode DIL_GetImage(DIL_Decoder decoder, DIL_ImageDesc* image_desc, DIL_Image* image);

DIL_ReleaseImage

Releases instance of DIL_Image

NOTE: No reference calls to image address should be made after this method

• decoder DIL instance

• image DIL_Image instance to be released

• return DIL API return code

DIL_ReturnCode DIL_ReleaseImage(DIL_Decoder decoder, DIL_Image image);

DIL_ImageGetDesc

Will return DIL_ImageDesc of the image

• image DIL_Image to query

• desc Contents of the pointer will be rewritten with image descriptions

• return DIL API return code

DIL_ReturnCode DIL_ImageGetDesc(DIL_Image image, DIL_ImageDesc* desc);

DIL_ImageSetActiveRegion

Will set the active region for an image

• image DIL_Image instance to modify

• offset_x X offset for the region

• offset_y Y offset for the region

• width width for the region

• height height for the region

• return DIL_RC_Error if crop region is out of bounds, image_type doesn't support cropping

DIL_ReturnCode DIL_ImageSetActiveRegion( DIL_Image                  image,
                                         uint32_t                   offset_x,
                                         uint32_t                   offset_y,
                                         uint32_t                   width,
                                         uint32_t                   height);

DIL_ImageGetActiveRegion

Will get the active region for an image

• image DIL_Image instance to modify

• offset_x X offset for the region

• offset_y Y offset for the region

• width width for the region

• height height for the region

• return DIL_RC_Error if crop region is out of bounds, image_type doesn't support cropping

DIL_ReturnCode DIL_ImageGetActiveRegion( DIL_Image                  image,
                                         uint32_t*                  offset_x,
                                         uint32_t*                  offset_y,
                                         uint32_t*                  width,
                                         uint32_t*                  height);

DIL_ImageGetPlanesCount

Will return number image's number of planes

• image DIL_Image to query

• plane_count Will be filled with number of planes

• return DIL API return code

DIL_ReturnCode DIL_ImageGetPlanesCount(DIL_Image image, uint32_t* plane_count);

DIL_ImageSetPlaneBuffer

Will set content and configurations of a plane by data buffer

• image DIL_Image instance to modify

• plane_index Index of the plane to modify

• buffer_desc DIL_ImagePlaneBufferDesc instance to read from

• return DIL_RC_Error if plane_index is out of bounds, image_type is not DIL_Buffer or image is managed

DIL_ReturnCode DIL_ImageSetPlaneBuffer( DIL_Image	                  image,
                                        uint32_t                    plane_index,
                                        DIL_ImagePlaneBufferDesc*   buffer_desc);

DIL_ImageGetPlaneBuffer

Will return content and configurations of a plane

• image DIL_Image to query

• plane_index Index of the plane to query

• buffer_desc DIL_ImagePlaneBufferDesc instance to write to

• return DIL_RC_Error if plane_index is out of bounds or image_type is not DIL_Buffer

DIL_ReturnCode DIL_ImageGetPlaneBuffer( DIL_Image                   image,
                                        uint32_t                    plane_index,
                                        DIL_ImagePlaneBufferDesc*   buffer_desc);

DIL_ImageSetPlaneTexture

Will set content and configurations of a plane by OpenGL/GLES texture

• image DIL_Image instance to modify

• plane_index Index of the plane to modify

• texture_desc DIL_ImagePlaneTextureDesc instance to read from

• return DIL_RC_Error if plane_index is out of bounds, image_type is not DIL_Texture or image is managed

DIL_ReturnCode DIL_ImageSetPlaneTexture( DIL_Image                  image,
                                         uint32_t                   plane_index,
                                         DIL_ImagePlaneTextureDesc* texture_desc);

DIL_ImageGetPlaneTexture

Will return content and configurations of a plane by OpenGL/GLES texture

• image DIL_Image instance to modify

• plane_index Index of the plane to modify

• texture_desc DIL_ImagePlaneTextureDesc instance to read from

• return DIL_RC_Error if plane_index is out of bounds, image_type is not DIL_Texture or image is managed

DIL_ReturnCode DIL_ImageGetPlaneTexture( DIL_Image                  image,
                                         uint32_t                   plane_index,
                                         DIL_ImagePlaneTextureDesc* texture_desc);

DIL_ImageSetPlaneHardwareBuffer

Will set content and configurations of a plane by OS specific Hardware buffer.

• image DIL_Image instance to modify

• plane_index Index of the plane to modify

• desc DIL_ImagePlaneHardwareBufferDesc instance to read from

• return DIL_RC_Error if plane_index is out of bounds, image_type is not DIL_Texture or image is managed

DIL_ReturnCode DIL_ImageSetPlaneHardwareBuffer( DIL_Image                         image,
                                                uint32_t                          plane_index,
                                                DIL_ImagePlaneHardwareBufferDesc* desc);

DIL_ImageGetPlaneHardwareBuffer

Will return content and configurations of a plane by OS specific Hardware buffer.

• image DIL_Image instance to query

• plane_index Index of the plane to query

• desc DIL_ImagePlaneHardwareBufferDesc instance to write to

• return Will return DIL_RC_Error if plane_index is out of bounds or image_type is not DIL_HardwareBuffer

DIL_ReturnCode DIL_ImageGetPlaneHardwareBuffer( DIL_Image                         image,
                                                uint32_t                          plane_index,
                                                DIL_ImagePlaneHardwareBufferDesc* desc);

DIL_ImageSetUserData

Will set the user data associated with the image

• image DIL_Image to set the userdata for

• userdata The userdata to associate with the image

• return DIL_RC_InvalidParam if the image, DIL_RC_Success otherwise

DIL_ReturnCode DIL_ImageSetUserData(DIL_Image image, void* userdata);

DIL_ImageGetUserData

Will get the user data associated with the image through DIL_ImageSetUserData

• image DIL_Image to get the userdata for

• userdata The userdata to associate with the image

• return DIL_RC_InvalidParam if the image is invalid or userdata is invalid, DIL_RC_Success otherwise

DIL_ReturnCode DIL_ImageGetUserData(DIL_Image image, void** userdata);

DIL_ImagePlaneHardwareBufferLock

Will return content and configurations of a plane buffer obtained by locking the hardware buffer for CPU access

• image DIL_Image to access

• plane_index Index of the plane to query

• read_access Whether we want read access

• write_access Whether we want write access

• buffer_desc DIL_ImagePlaneBufferDesc instance to write to

• return Will return DIL_RC_Error if plane_index is out of bounds or image_type is not DIL_HardwareBuffer

DIL_ReturnCode DIL_ImagePlaneHardwareBufferLock( DIL_Decoder                 decoder,
                                                 DIL_Image                   image,
                                                 uint32_t                    plane_index,
                                                 bool                        read_access,
                                                 bool                        write_access,
                                                 DIL_ImagePlaneBufferDesc*   buffer_desc);

DIL_ImagePlaneHardwareBufferUnlock

Will unlock the hardware buffer plane once CPU access is completed.

• image DIL_Image to unlock

• plane_index Index of the plane to query

• return Returns DIL_RC_Error if plane_index is out of bounds or image_type is not DIL_HardwareBuffer

DIL_ReturnCode DIL_ImagePlaneHardwareBufferUnlock( DIL_Decoder                 decoder,
                                                   DIL_Image                   image,
                                                   uint32_t                    plane_index);

DIL_AddTSData

Feed Transport Stream packet(s) for the DIL to extract and store LCEVC data, feed a buffer of TS packets associated with the Access Unit identified by input cc and timestamp

NOTE: input_cc is a feed counter identifying which feed the passed data belongs to, the client shall increment its value every time the input changes, typically because of a playback position change or a rendition change in an ABR playback

NOTE: input_cc shall have monotonically increasing value over calls

• decoder DIL instance

• input_cc input continuity counter

• data pointer to the TS buffer

• size size of the TS buffer

• returns DIL API return code

DIL_ReturnCode DIL_AddTSData( DIL_Decoder           decoder,
                              uint16_t              input_cc,
                              uint8_t*              data,
                              uint32_t              size );

DIL_AddWebmData

Feed Webm payload for the DIL to extract and store LCEVC data

• decoder DIL instance

• input_cc input continuity counter

• data pointer to the TS buffer

• size size of the TS buffer

• returns DIL API return code

DIL_ReturnCode DIL_AddWebmData( DIL_Decoder         decoder,
                                uint16_t            input_cc,
                                uint8_t*            data,
                                uint32_t            size );

DIL_AddNALData

Feed NAL unit(s) for the DIL to extract and store LCEVC data, feed a buffer of NAL units associated with the Access Unit identified by input cc and timestamp

NOTE: input_cc is a feed counter identifying which feed the passed data belongs to, the client shall increment its value every time the input changes, typically because of a playback position change or a rendition change in an ABR playback

NOTE: input_cc shall have monotonically increasing value over calls

NOTE: timestamp shall have monotonically increasing value over calls within the same input_cc

• decoder DIL instance

• input_cc input continuity counter

• timestamp time reference for the passed NAL units

• data pointer to the NAL units buffer

• size size of the NAL units buffer

• nalu_format format of the NAL units

• return DIL API return code

DIL_ReturnCode DIL_AddNALData( DIL_Decoder          decoder,
                               uint16_t             input_cc,
                               int64_t              timestamp,
                               uint8_t*             data,
                               uint32_t             size,
                               DIL_NALFormat        nalu_format );

DIL_AddNALDataEx

Feed NAL unit(s) for the DIL to extract and store LCEVC data (Extended), feed a buffer of NAL units associated with the Access Unit identified by input cc and timestamp and additionally let the DIL strip the LCEVC payloads and zero pad the trailing bytes, returning the new size before padding

NOTE: input_cc is a feed counter identifying which feed the passed data belongs to, the client shall increment its value every time the input changes, typically because of a playback position change or a rendition change in an ABR playback

NOTE: input_cc shall have monotonically increasing value over calls

NOTE: timestamp shall have monotonically increasing value over calls within the same input_cc

• decoder DIL instance

• input_cc input continuity counter

• timestamp time reference for the passed NAL units

• data pointer to the NAL units buffer

• size size of the NAL units buffer

• nalu_format format of the NAL units

• return size of the stripped NAL units buffer

uint32_t DIL_AddNALDataEx( DIL_Decoder              decoder,
                           uint16_t                 input_cc,
                           int64_t                  timestamp,
                           uint8_t*                 data,
                           uint32_t                 size,
                           DIL_NALFormat            nalu_format );

DIL_AddRawData

Feed LCEVC data to the DIL, feed a buffer of pre parsed LCEVC payload data for the Access Unit identified by input cc and timestamp

NOTE: input_cc is a feed counter identifying which feed the passed data belongs to, the client shall increment its value every time the input changes, typically because of a playback position change or a rendition change in an ABR playback

NOTE: input_cc shall have monotonically increasing value over calls

NOTE: timestamp shall have monotonically increasing value over calls within the same input_cc

• decoder DIL instance

• input_cc input continuity counter

• timestamp time reference for the passed LCEVC data

• data pointer to the NAL units buffer

• size size of the NAL units buffer

• return DIL API return code

DIL_ReturnCode DIL_AddRawData( DIL_Decoder          decoder,
                               uint16_t             input_cc,
                               int64_t              timestamp,
                               uint8_t*             data,
                               uint32_t             size );

DIL_GetDecodeInformation

Get details about the decoding process for the Access Unit identified by input cc and timestamp

• decoder DIL instance

• input_cc input continuity counter

• timestamp time reference of the picture

• base_width width of the base decoded picture

• base_height height of the base decoded picture

• information pointer to decoder information structure that the DIL will fill

• return DIL API return code

DIL_ReturnCode DIL_GetDecodeInformation( DIL_Decoder                    decoder,
                                         uint16_t                       input_cc,
                                         int64_t                        timestamp,
                                         uint32_t                       base_width,
                                         uint32_t                       base_height,
                                         DIL_DecodeInformation*         information );

DIL_Decode

Decode on to an off screen DIL_Image, get an off screen LCEVC enhanced (or base pass-through) picture from the input base picture relative to input cc and timestamp

• decoder DIL instance

• input_cc input continuity counter

• timestamp time reference of the picture to be decoded

• max_decode_time_us maximum amount of time the decode has to complete, use 0 to disable decode timeout

• input pointer to decoded base picture for input cc and timestamp (it may be modified if DIL operates in CPU mode)

• output pointer to LCEVC enhanced (or base pass-through) output picture

• decode_information pointer to decoder information structure that the DIL will fill (if DIL_SetDecodedAsyncCallback has not been called)

• return DIL API return code

DIL_ReturnCode DIL_Decode( DIL_Decoder                      decoder,
                           uint16_t                         input_cc,
                           int64_t                          timestamp,
                           uint32_t                         max_decode_time_us,
                           DIL_Image*                       input,
                           DIL_Image*                       output,
                           DIL_DecodeInformation*           decode_information );

DIL_Render

Render to back buffer a previously decoded DIL_Image

NOTE: for the scheduled render to be set DIL_SetRenderAsyncCallback must have been previously called

• decoder DIL instance

• input_cc input continuity counter

• timestamp time reference of the picture to be rendered

• image pointer to a picture to be rendered to back buffer

• render_information pointer to a render information structure

• delay_us delay in microseconds for the render to eb executed (0 for no delay)

• return DIL API return code

DIL_ReturnCode DIL_Render( DIL_Decoder                      decoder,
                           uint16_t                         input_cc,
                           int64_t                          timestamp,
                           DIL_Image                        image,
                           const DIL_RenderInformation*     render_information,
                           int64_t                          delay_us );

DIL_DecodeAndRender

Decode and render immediately to back buffer

• decoder DIL instance

• input_cc input continuity counter

• timestamp time reference of the picture to be decoded and rendered

• max_decode_time_us maximum amount of time the decode has to complete, use 0 to disable decode timeout

• input pointer to decoded base picture for input cc and timestamp (it may be modified if DIL operates in CPU mode)

• render_information pointer to a render information structure

• decode_information pointer to decoder information structure that the DIL will fill (if DIL_SetDecodedAsyncCallback has not been called)

• return DIL API return code

DIL_ReturnCode DIL_DecodeAndRender( DIL_Decoder                         decoder,
                                    uint16_t                            input_cc,
                                    int64_t                             timestamp,
                                    uint32_t                            max_decode_time_us,
                                    DIL_Image                           input,
                                    const DIL_RenderInformation*        render_information,
                                    DIL_DecodeInformation*              decode_information );

DIL_DecodeSkip

Let the DIL know that an Access Unit is not being presented (dropped or skipped), DIL will do the minimum processing to keep internal state consistent for the next picture

NOTE: this call will generate a DecodeAsyncCallback if previously set

NOTE: calling this on an IDR Access Unit is undefined behaviour

• decoder DIL instance

• input_cc input continuity counter

• timestamp time reference for the Access Unit to be skipped

• return DIL API return code

DIL_ReturnCode DIL_DecodeSkip( DIL_Decoder              decoder,
                               uint16_t                 input_cc,
                               int64_t                  timestamp );

DIL_Flush

Synchronize client and DIL by throwing away any pending decodes and renders and waiting for all callbacks to complete

NOTE: all callbacks set by DecodeAsyncCallback and RenderAsyncCallback will be called with a the result filed in the callback will indicate the error DIL_RC_Flushed making DIL calls in this callback could result in a deadlock use the DIL_SetFlushAsyncCallback to break this loop

• decoder DIL instance

• return DIL API return code

DIL_ReturnCode DIL_Flush( DIL_Decoder              decoder );

DIL_Drain

synchronize client and DIL by allowing any pending decodes and renders to complete and waiting for all callbacks to complete

NOTE: all callbacks set by DecodeAsyncCallback and RenderAsyncCallback will be called making DIL calls in this callback could result in a deadlock use the DIL_SetDrainAsyncCallback to break this loop

• decoder DIL instance

• return DIL API return code

DIL_ReturnCode DIL_Drain( DIL_Decoder              decoder );

DIL_GetGLContext

Get the DIL's GL Context

• decoder DIL instance

• context pointer to pointer of GL Context

• return DIL API return code

DIL_ReturnCode DIL_GetGLContext( DIL_Decoder            decoder,
                                 void**                 context );

DIL_GetGLDisplay

Get the DIL's GL Display

• decoder DIL instance

• display pointer to pointer of GL Display

• return DIL API return code

DIL_ReturnCode DIL_GetGLDisplay( DIL_Decoder            decoder,
                                 void**                 display);

DIL_SetGLWindow

Set the DIL's GL output window

• decoder DIL instance

• gl_external_window pointer to destination window

• is_secure true if the destination window is secure

• return DIL API return code

DIL_ReturnCode DIL_SetGLWindow( DIL_Decoder             decoder,
                                void*                   gl_external_window,
                                bool                    is_secure );

DIL_SetExitRequestedCallback

Set ExitRequest call back function

• decoder DIL instance

• callback pointer to DILOnExitRequestedCallBack function

• user_data pointer to client's user data

• return DIL API return code

typedef void (*DILOnExitRequestedCallBack)( void* user_data );

DIL_ReturnCode DIL_SetExitRequestedCallback( DIL_Decoder                    decoder,
                                             DILOnExitRequestedCallBack     callback,
                                             void*                          user_data);

DIL_SetDecodedAsyncCallback

Set asynchronous on decoded call back function

• result result of the decode request, see DIL_ReturnCode

• input_cc input continuity counter

• timestamp time reference of the picture that was decoded

• input pointer to base input picture, the same passed in the previous DIL_Decode

• output pointer to LCEVC enhanced (or base pass-through) output picture, the same passed in the previous DIL_Decode

• information pointer to decoder information structure (not the same passed in from the previous DIL_Decode)

• user_data pointer to the same client's user data that was passed into the DIL_SetDecodedAsyncCallback

• decoder DIL instance

• callback pointer to DILOnDecodedAsyncCallBack function

• user_data pointer to client's user data

• return DIL API return code

typedef void (*DILOnDecodedAsyncCallBack)( DIL_ReturnCode                   result,
                                           uint16_t                         input_cc,
                                           int64_t                          timestamp,
                                           DIL_Image                        input,
                                           DIL_Image                        output,
                                           const DIL_DecodeInformation*     information,
                                           void*                            user_data );

DIL_ReturnCode DIL_SetDecodedAsyncCallback( DIL_Decoder                     decoder,
                                            DILOnDecodedAsyncCallBack       callback,
                                            void*                           user_data );

DIL_SetRenderAsyncCallback

Set asynchronous on render callback function

• result result of render request, see DIL_ReturnCode

• completion_time_us actual time in microseconds the render completed

• input_cc input continuity counter

• timestamp time reference of the picture that was rendered

• output pointer to the same picture passed in with the DIL_Render method

• user_data pointer to the same client's user data that was passed into the DIL_SetRenderAsyncCallback

• decoder DIL instance

• callback pointer to DILOnRenderAsyncCallBack function

• user_data pointer to client's user data

• return DIL API return code

typedef void (*DILOnRenderAsyncCallBack)( DIL_ReturnCode          result,
                                          int64_t                 completion_time_us,
                                          uint16_t                input_cc,
                                          int64_t                 timestamp,
                                          DIL_Image               output,
                                          void*                   user_data );
                                          
DIL_ReturnCode DIL_SetRenderAsyncCallback( DIL_Decoder                      decoder,
                                           DILOnRenderAsyncCallBack         callback,
                                           void*                            user_data );

DIL_SetRenderResizeAsyncCallback

Called at the start of the render process when the image to be displayed has a different size to the last image rendered. This is a blocking call and there should be no DIL calls in the callback function.

• result result of render request, see DIL_ReturnCode

• completion_time_us actual time in microseconds the render completed

• input_cc input continuity counter

• timestamp time reference of the picture that was rendered

• output pointer to the same picture passed in with the DIL_Render method

• user_data pointer to the same client's user data that was passed into the DIL_SetRenderAsyncCallback

• decoder DIL instance

• callback pointer to DILOnRenderAsyncCallBack function

• user_data pointer to client's user data

• return DIL API return code

typedef void (*DILOnRenderAsyncCallBack)( DIL_ReturnCode          result,
                                          int64_t                 completion_time_us,
                                          uint16_t                input_cc,
                                          int64_t                 timestamp,
                                          DIL_Image               output,
                                          void*                   user_data );

DIL_ReturnCode DIL_SetRenderResizeAsyncCallback( DIL_Decoder                      decoder,
                                                 DILOnRenderAsyncCallBack         callback,
                                                 void*                            user_data );

DIL_SetFlushAsyncCallback

Callback function for the DIL_Flush() function

• user_data pointer to client's user data

• decoder DIL instance

• callback pointer to DILOnSynchronizeCallBack function

• user_data pointer to client's user data

• return DIL API return code

typedef void (*DILOnSynchronizeCallBack)( void* user_data );

DIL_ReturnCode DIL_SetFlushAsyncCallback( DIL_Decoder                      decoder,
                                          DILOnSynchronizeCallBack         callback,
                                          void*                            user_data );

DIL_SetDrainAsyncCallback

Callback function for the DIL_Drain() function

• user_data pointer to client's user data

• decoder DIL instance

• callback pointer to DILOnSynchronizeCallBack function

• user_data pointer to client's user data

• return DIL API return code

typedef void (*DILOnSynchronizeCallBack)( void* user_data );

DIL_ReturnCode DIL_SetDrainAsyncCallback( DIL_Decoder                      decoder,
                                          DILOnSynchronizeCallBack         callback,
                                          void*                            user_data );

DIL_InputMouseButtonState

Pass the DIL the position of the input mouse button

• decoder DIL instance

• pressed true if button is pressed

• return DIL API return code

DIL_ReturnCode DIL_InputMouseButtonState( DIL_Decoder             decoder,
                                          bool                    pressed );

DIL_InputMousePosition

Pass the DIL the position of the input mouse

• decoder DIL instance

• x horizontal coordinate of the mouse cursor

• y vertical coordinate of the mouse cursor

• return DIL API return code

DIL_ReturnCode DIL_InputMousePosition( DIL_Decoder                decoder,
                                       float                      x,
                                       float                      y );

DIL Types and Enumerations

DIL_NALFormat enum

DIL_NALFormat represents the two possible NAL Unit formats, for each of the MPEG base codecs the DIL currently supports: H264 (ISO/IEC 14496-10, aka AVC) and H265 (ISO/IEC 23008-2, aka HEVC) NAL, where Annex B indicates 3 byte 0x000001 or 4 byte 0x00000001 start code prefix as described in Annex B of (H264 or HEVC), LP (Length Prefix) indicates a 4 byte prefix with the length of the NAL unit as MSBF 32 bit unsigned int.

typedef enum DIL_NALFormat
{
    DIL_UnknownNALFormat = 0,
    DIL_H264_AnnexB,
    DIL_H265_AnnexB,
    DIL_H264_LP,
    DIL_H265_LP
} DIL_NALFormat;

DIL_ReturnCode enum

DIL_ReturnCode represents the possible API return codes. Most of the API calls will return one of these values.

typedef enum DIL_ReturnCode
{
    DIL_RC_Success      =  0,       /* The API call completed successfully */
    DIL_RC_Error        = -1,       /* A generic catch all error */
    DIL_RC_InvalidParam = -2,       /* The user supplied an invalid parameter to the function call */
    DIL_RC_NotFound     = -3,       /* The query call failed to find the item by name, but didn't not generate an error. */
    DIL_RC_NotSupported = -4,       /* The functionality requested is not supported on the running system. */
    DIL_RC_Flushed      = -5,       /* The requested operation failed because it was flushed via DIL_Flush. */
    DIL_RC_Timeout      = -6        /* The requested operation failed because it timedout. */
} DIL_ReturnCode;

DIL_ColorFormat enum

This enum represents the supported colour formats, currently only 8 bit per sample formats are supported For a detailed description of the formats see: https://gstreamer.freedesktop.org/documentation/additional/design/mediatype-video-raw.html

typedef enum DIL_ColorFormat
{
    DIL_UnknownColorFormat = 0,     /* Unspecified colour format */
    DIL_I420_8,                     /* 8 bit 4:2:0 YUV Planar colour format: Y, U and V on separate planes */
    DIL_NV12_8,                     /* 8 bit 4:2:0 YUV SemiPlanar colour format: Y plane and UV interleaved plane */
    DIL_RGB_8,                      /* 8 bit Interleaved R, G, B planes 24 bit per sample */
    DIL_RGBA_8,                     /* 8 bit Interleaved R, G, B and A planes 32 bit per sample */
    DIL_I420_10LE,                  /* 10 bit Little Endian 4:2:0 YUV Planar colour format: Y, U and V on separate planes */

} DIL_ColorFormat;

DIL_ImageType enum

This enum identifies the type of planes the DIL_Image consists of; planes are non-overlapping sets of samples belonging to one or more colour channels with a constant sample stride, so RGB is a single plane, because R G and B pointed at separately would overlap UV from NV12 is a single plane, because U and V pointed at separately would overlap Y U and V from I420 are three planes because they do not overlap

typedef enum DIL_ImageType
{
    DIL_UnknownImageType = 0,       /* Unspecified image type */
    DIL_Buffer_Array,               /* One buffer per plane, even if image is on a single memory allocation, an array of planes shall be set by assigning the right pointers to plane buffers. DIL allocated buffers have contiguous memory allocation */
    DIL_Texture_Array,              /* One texture per plane, typically in YUV colour formats, it consists of a single plane, even for YUV, if GL YUV extension is used */
    DIL_HardwareBuffer_Array        /* One HardwareBuffer per plane, typically in YUV colour formats, it consists of a single plane, even for YUV, if GL YUV extension is used */
} DIL_ImageType;

DIL_ImageDesc struct

Holds configurations of a single DIL_Image instance

typedef struct DIL_ImageDesc
{
    bool            is_managed;     /* True means that Image (and its memory) is managed by DIL  */
    DIL_ImageType   image_type;     /* Whether it is a buffer array or a texture array */
    DIL_ColorFormat color_format;   /* Colour format */
	  uint32_t        width;          /* Nominal net width of the image in luma samples, i.e. no alignment to macroblocks or striding */
    uint32_t        height;         /* Nominal net height of the image in luma samples, i.e. no sliceheight or padding */
    bool            can_modify;     /* Specifying wether content of image is readOnly or changable */
    bool            can_resize;     /* Specifying wether allocated memory is resizable or not. (Does not apply to DIL_Buffer_External) */
    uint32_t        options;        /* options used in creating the Image, in the case of HardwareBuffers this is a combination of  DIL_HardwareBufferUsageOption */
} DIL_ImageDesc;

DIL_ContextSettings struct

This structure holds parameters related to the window surface the DIL would render into, in case of on screen rendering those parameters are normally provided by the windowing system, e.g. EGL, GLFW.

typedef struct DIL_ContextSettings
{
    void* gl_external_window;       /* Surface window, from the windowing system */
    void* gl_external_context;      /* Context, from the windowing system */
    bool  is_secure;                /* True if the client has initialised window and context as secure for protected content */
} DIL_ContextSettings;

DIL_RenderInformation struct

This structure captures the properties related to the (on screen) window rendering, they do not apply for buffer or texture output (off screen). NOTE: rotation is a per frame property because it may change frame by frame due to for ex. the encoding device rotating while shooting.

typedef struct DIL_RenderInformation
{
    uint32_t rotation;                  /* Degrees of rotation for the final rendering on the destination window, in 90 unit increments clockwise */
    float    pixel_aspect_ratio_num;    /* Pixel Aspect Ratio of width to height, this is the numerator, par = (pixel_aspect_ratio_num)/(pixel_aspect_ratio_den) */
    float    pixel_aspect_ratio_den;    /* Pixel Aspect Ratio of width to height, this is the denominator, par = (pixel_aspect_ratio_num)/(pixel_aspect_ratio_den) */
} DIL_RenderInformation;

DIL_DecodeInformation struct

This structure captures properties related to the decoding process, width and height of the output, whether LCEVC data has been found and whether it has been applied.

typedef struct DIL_DecodeInformation
{
    uint32_t width;                     /* width of the decoded frame */
    uint32_t height;                    /* height of the decoded frame */
    bool     skip_requested;            /* decode skip was requested */
    bool     lcevc_enhanced;            /* true if the frame has been enhanced by lcevc decoding */
    bool     lcevc_available;           /* true if lcevc encoded data is available for this frame */
} DIL_DecodeInformation;

DIL_ImagePlaneBufferDesc struct

This struct describes a plane memory buffer

typedef struct DIL_ImagePlaneBufferDesc
{
    uint8_t* data;                      /* Pointer to first byte of the first active sample of the plane buffer, NOTE: active means no cropping, the active origin is 0,0 */
    uint32_t sample_byte_stride;        /* Distance in bytes between consecutive sample values of the same channel, for ex. UV plane on 8bit depth this will be 2 */
    uint32_t row_byte_stride;           /* Distance in bytes between the first sample of two consecutive rows */
} DIL_ImagePlaneBufferDesc;

DIL_ImagePlaneTextureDesc struct

This struct describes a plane OpenGL texture

typedef struct DIL_ImagePlaneTextureDesc
{
    uint32_t target;                /* OpenGL/GLES texture target, as in glBindTexture target */
    uint32_t id;                    /* OpenGL/GLES texture id. Unused indexes should be set to 0 */
    uint32_t width;                 /* OpenGL/GLES texture width, which might have extra padding, NOTE: the active width is in the parent Image struct */
    uint32_t height;                /* OpenGL/GLES texture height, which might have extra padding, NOTE: the active height is in the parent Image struct */
    int32_t  internal_format;       /* OpenGL/GLES (GLint) sized internal format as from Table 2 of glTexImage2D man page */
} DIL_ImagePlaneTextureDesc;

DIL_HardwareBufferUsageOption enum

This enum use used to set the UsageOption when creating HardwareBuffer DIL_Image types. It should be provided in the "hardware_buffer_usage_option" tag when configuring the DIL object

typedef enum DIL_HardwareBufferUsageOption
{
    UsageOption_None = 0,

    UsageOption_Read_Never  = (1 << 0),
    UsageOption_Read_Rarely = (1 << 1),
    UsageOption_Read_Often  = (1 << 2),

    UsageOption_Write_Never  = (1 << 4),
    UsageOption_Write_Rarely = (1 << 5),
    UsageOption_Write_Often  = (1 << 6),

    UsageOption_Protected_Content = (1 << 7),

    UsageOption_GPU_Read          = (1 << 8),
    UsageOption_GPU_Write         = (1 << 9)
} DIL_HardwareBufferUsageOption;

DIL_ImagePlaneHardwareBufferDesc struct

This struct describes a plane HardwareBuffer

typedef struct DIL_ImagePlaneHardwareBufferDesc
{
    uint32_t width;                 /* width, which might have extra padding, NOTE: the active width is in the parent Image struct */
    uint32_t height;                /* height, which might have extra padding, NOTE: the active height is in the parent Image struct */
		void*    nativeObject;          /* platform native object/id for the HardwareBuffer */
} DIL_ImagePlaneHardwareBufferDesc;

DIL Properties API

DIL_QueryProperty

Obtain a specific named property. This function provides a way of looking up a property by name to observe it's current value, this may be of use for a user to query DIL properties

DIL_ReturnCode DIL_QueryProperty(DIL_Decoder decoder, const char* name, DILProperty* output);

DIL_SetProperty

Set a specific named property. This function provides a way of changing a property by name

DIL_ReturnCode DIL_SetProperty(DIL_Decoder decoder, const char* name, DILProperty* value);

DIL_QueryPropertyGroup

Obtain all the available properties for a named group

DIL_ReturnCode DIL_QueryPropertyGroup(DIL_Decoder decoder, const char* name, DILPropertyGroup* output);

DIL_ReleaseProperty

Release a previously queried property, this function provides a way of releasing any memory allocated by a call to DIL_QueryProperty. Any data contained in value maybe invalidated after this call

DIL_ReturnCode DIL_ReleaseProperty(DIL_Decoder decoder, DILProperty* value);

DIL_ReleasePropertyGroup

Release a previously queried property group, this function provides a way of releasing any memory allocated by a call to DIL_QueryPropertyGroup Any data contained in value maybe invalidated after this call

DIL_ReturnCode DIL_ReleasePropertyGroup(DIL_Decoder decoder, DILPropertyGroup* value);

DILProperty struct.

This structure contains all relevant information used to query a property or metadata from the DIL.

typedef struct DILProperty
{
  const char*     name;        /* The name of the property.  */
  const char*     description; /* A description of the property. */
  DILPropertyType type;        /* The value type for this property. */
  union
  {
    int8_t      i8;
    int16_t     i16;
    int32_t     i32;
    int64_t     i64;
    uint8_t     u8;
    uint16_t    u16;
    uint32_t    u32;
    uint64_t    u64;
    float       f;
    double      d;
    const char* str;
    const void* vptr;
    const void* data;
		const DILPropertyGroup* pgptr;
  } value;                  /* A union representing the value of the property. The user must read the field that match the type enum value. */

  const uint8_t* blob;      /* Special field containing a block of contiguous memory when the type enum is set to DIL_PT_Blob. This is allowed to be NULL. */
  uint32_t       blob_size; /* When the blob is not NULL then the length in bytes of the memory, otherwise 0. */
	uint64_t       data_size; /* size of the "data" buffer in bytes */
	bool           can_free;  /* flag to show if the pointer values should be free'ed when the DIL_ReleaseProperty is called */
} DILProperty;

DILPropertyGroup struct.

This structure contains a logical grouping of properties, this is a convenience feature to assist with providing a "pretty" command line, or GUI.

All properties are assigned to a group, and properties can only appear in one group.

typedef struct DILPropertyGroup_t
{
  const char*  name;           /* The name for this group of properties. */
  const char*  description;    /* A description of the property group. */
  DILProperty* properties;     /* An array of properties for this group. */
  uint32_t     property_count; /* The length of the properties array. */
	bool         can_free;       /* flag to show if the properties pointer should be free'ed when the DIL_ReleaseProperty is called */
} DILPropertyGroup;