private void readDecodedFrames(AVFrame *receiveFrame) { while (true) { int receiveFrameResult = ffmpeg.avcodec_receive_frame(codecContext, receiveFrame); if (receiveFrameResult < 0) { if (receiveFrameResult != -AGffmpeg.EAGAIN && receiveFrameResult != AGffmpeg.AVERROR_EOF) { Logger.Log($"Failed to receive frame from avcodec: {getErrorMessage(receiveFrameResult)}"); } break; } // use `best_effort_timestamp` as it can be more accurate if timestamps from the source file (pts) are broken. // but some HW codecs don't set it in which case fallback to `pts` long frameTimestamp = receiveFrame->best_effort_timestamp != AGffmpeg.AV_NOPTS_VALUE ? receiveFrame->best_effort_timestamp : receiveFrame->pts; double frameTime = (frameTimestamp - stream->start_time) * timeBaseInSeconds * 1000; if (skipOutputUntilTime > frameTime) { continue; } // get final frame. FFmpegFrame frame; if (((AVPixelFormat)receiveFrame->format).IsHardwarePixelFormat()) { // transfer data from HW decoder to RAM. if (!hwTransferFrames.TryDequeue(out var hwTransferFrame)) { hwTransferFrame = new FFmpegFrame(ffmpeg, returnHwTransferFrame); } // WARNING: frames from `av_hwframe_transfer_data` have their timestamps set to AV_NOPTS_VALUE instead of real values. // if you need to use them later, take them from `receiveFrame`. int transferResult = ffmpeg.av_hwframe_transfer_data(hwTransferFrame.Pointer, receiveFrame, 0); if (transferResult < 0) { Logger.Log($"Failed to transfer frame from HW decoder: {getErrorMessage(transferResult)}"); // dispose of the frame instead of enqueueing it in case that the failure was caused by it's configuration. hwTransferFrame.Dispose(); continue; } frame = hwTransferFrame; } else { // copy data to a new AVFrame so that `receiveFrame` can be reused. frame = new FFmpegFrame(ffmpeg); ffmpeg.av_frame_move_ref(frame.Pointer, receiveFrame); } lastDecodedFrameTime = (float)frameTime; // Note: this is the pixel format that `VideoTexture` expects internally frame = ensureFramePixelFormat(frame, AVPixelFormat.AV_PIX_FMT_YUV420P); if (frame == null) { continue; } if (!availableTextures.TryDequeue(out var tex)) { tex = new Texture(new VideoTexture(frame.Pointer->width, frame.Pointer->height)); } var upload = new VideoTextureUpload(frame); tex.SetData(upload); decodedFrames.Enqueue(new DecodedFrame { Time = frameTime, Texture = tex }); } }