DJI Windows 10 SDK FFMPEG视频缓冲

Question

Does anyone know how to reduce the buffering latency of the DJI FFMPEG implementation? It seems as though the longer an application runs using this API, the worse the latency becomes. Are there specific options other than CODEC_FLAG_LOW_DELAY or CODEC_FLAG2_FAST which might help reduce the latency? Is there something that I should be setting in the av_parser_parse2 to reduce the delay? I am of course presuming the latency is in the API rather that the aircraft itself - it just doesn't seem likely that the UAV has the storage to buffer large amounts of video.

Answer 1

After some experimentation, I discovered that the pts/dts values of the av_parser_parse2 method will impact frame buffering. DJI's sample code uses AV_NOPTS_VALUE for both pts and dts; this leads to ever-increasing latency in the video stream. Rather than calculate these values, I simply increment pts by 1000 for every time got_picture == true and set dts = pts. Yep, it's a hack but it works. Hopefully this will help others who encounter this issue as well. If you're using the DJIVideoParser project, this change can easily be made to the h264_Decoder.cpp's DecoderThread method.