[Libav-user] Best way to provide avcodec_decode_video2 with h264 data?

Tim Pitman tapitman11 at gmail.com
Thu Oct 25 00:14:53 CEST 2012

Yeah I finally got the decoder working on a frame to frame basis and
got rid of the constant errors, at least as long as the stream is

I'm confused what you mean by "The encoder expects NAL units". I'm
piping raw video data (via ffmpeg using yuv4mpegpipe format) into x264
which seems to work.

Two questions for you?

1) Is live555 suitable for lossy physical layer transmissions or only
for situations with a working UDP or TCP network?

2) Sometimes the video gets so corrupted over the wireless channel
that the decoder seems to get stuck printing a constant series of
errors and doesn't recover, even if the channel improves. Do you know
of a way to restart or flush the decoder some way, or another way to
get around this?


On Wed, Oct 24, 2012 at 2:46 AM, Tony Glover <T.Glover at nottingham.ac.uk> wrote:
> Hi Tim,
>         I've also been using intra-refresh to stream h264 video. The encoder expects NAL units and, after encoding, the data is streamed in packets. Your frame may or may not fit your encoded frame into a single packet, depending on its size. At the receiving end, you should wait until you receive all the data corresponding to a frame which you can then send to your decoder.
> I use x264 to do the encoding, live555 to do the streaming and ffmpeg to do the decoding. There are a lot of examples in the live555 codebase so you shouldn't have a problem in seeing an example of what you are intending to do.
> Hope this helps,
> Tony.
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