By the way, you can find the stream header in AVCodecContext::extradata after avformat_find_stream_info() call.
2013/6/14 Sergey Fedorov <[email protected]> > H.264 Video > Types<http://msdn.microsoft.com/en-us/library/windows/desktop/dd757808%28v=vs.85%29.aspx>: > > >> The MP4 container format stores H.264 data without start codes. Instead, >> each NALU is prefixed by a length field, which gives the length of the NALU >> in bytes. The size of the length field can vary, but is typically 1, 2, or >> 4 bytes. >> > > See also: H.264 extradata (partially) explained - for > dummies<http://aviadr1.blogspot.ru/2010/05/h264-extradata-partially-explained-for.html> > > > > 2013/6/13 Anshul maheshwari <[email protected]> > >> U can try using gdb, put a brk point on above line u provided, >> Print the pkt, >> If trouble using gdb, reply me I wud do fr u! >> It was never required to me! >> >> Anshul >> On Jun 13, 2013 10:16 PM, "Arvind Raman" <[email protected]> wrote: >> >>> Question - What is the format in which audio / video ES data is stored >>> in (AVPacket*) pkt->data? I am trying to demux and decode AV data from >>> a MP4 file using libavformat and libavcodec. >>> >>> More details >>> >>> 1. Using the sample application demuxing.c ( >>> http://www.ffmpeg.org/doxygen/trunk/demuxing_8c_source.html) I tried >>> demuxing and decoding a MP4 file containing H.264 video and AACaudio. >>> 2. While the sample application worked fine, I wasn't able to >>> interpret the content in the pkt.data buffer (line #66 in the above >>> file). >>> Since the video was H.264 I was hoping to see familiar "nal_unit_type" >>> but I don't think I saw that for the stream I was trying to decode. If I >>> remember the data correctly the first 4 bytes in the pkt.data buffer were >>> "0x00 0x00 0x02 0x72" >>> >>> I haven't spent much time figuring this out yet but searching on the >>> Internet / forum didn't help. I intend to dig deeper tomorrow, but just >>> wanted to check if indeed ES was being passed in the pkt.data buffers in a >>> special way. >>> >>> Appreciate any points that you can provide. >>> >>> Best regards >>> Arvind >>> >>> >>> _______________________________________________ >>> Libav-user mailing list >>> [email protected] >>> http://ffmpeg.org/mailman/listinfo/libav-user >>> >>> >> _______________________________________________ >> Libav-user mailing list >> [email protected] >> http://ffmpeg.org/mailman/listinfo/libav-user >> >> >
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