Hi Eric, Regarding #3, those are the SPS and PPS NAL units, size 22 and 4 respectively. You can confirm by looking at the 5 lower bits of the first byte and matching the NAL unit type with values 7 and 8 for SPS and PPS.
Some RTSP sources provide them in a separate stream while others embed them together with the video stream, as it appears in your case. You can read more about it in ISO 14496-10. Thanks, Chris On Thu, May 30, 2019 at 5:16 PM <eric.bra...@nikon.com> wrote: > Hello, > > > > I am streaming the test.264 file from live555 using the > testOnDemandRTSPServer. > > I am receiving it using testRTSPClient. This part works fine. > > > > I have modified testRTSPClient with a custom Sink such that the > ‘afterGettingFrame’ virtual function passes the contents of each > fReceiveBuffer to libav/ffmpeg’s av_parser_parse2() to parse the incoming > data into packets, later to be submitted to avcodec_send_packet() and > avcodec_receive_frame() pair to decode it. I can use this same > av_parser_parse2()/avcodec_send_packet()/avcodec_receive_frame() to > properly decode frames by supplying bytes to the parser directly from the > test.264 file (using fopen()/fread()), so I know that part of the pipeline > works if the incoming data is correct. > > > > However, when supplying the fReceiveBuffer data from > ‘afterGettingFrame()’, the av_parser_parse2() never finds a packet, because > the testRTSPClient has consumed the 0x0001 header at the start of the h.264 > packet. I have several questions, all of which center around how to > properly decode data arriving through afterGettingFrame(). > > > > 1. Is there a way to prevent the testRTSPClient infrastructure from > consuming that header byte so that I can supply it to the parser? > > 2. If I should not use the av_parser_parse2() function to find > packets, then how do I properly segment the data coming in via > afterGettingFrame() into packets that I can supply to the > avcodec_send_packet()/avcodec_receive_frame()? > > 3. The sizes of the data received in fReceiveBuffer are clearly not > entire frames…in fact the first few times the function is called the data > sizes are 22, 4, 3017, 3081… Why the small size callbacks every so often? > > > > Any help you can provide generally on how to supply data being received by > testRTSPClient to libav/ffmpeg decoder would be very much appreciated. > > > > Thanks, > > -Eric. > > > _______________________________________________ > live-devel mailing list > live-devel@lists.live555.com > http://lists.live555.com/mailman/listinfo/live-devel >
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