[Libav-user] There is no picture in the output file while encoding with libx264 as codec.

Alex Cohn alexcohn at netvision.net.il
Tue Dec 25 16:55:19 CET 2012

On Tue, Dec 25, 2012 at 11:08 AM, Brian Chi <beyond702 at gmail.com> wrote:
> I tracked the ffmpeg code and found that in the function
> "av_write_frame->mov_write_packet->ff_mov_write_packet", it will call
> function "ff_avc_parse_nal_units" to obtain the size of nal unit, but the
> return value is very small(such as 208 bytes).

It's very natural for the first NAL unit to be small. An h264 stream
begins with configuration SPS/PPS untis that don't contain video data,
but let the decoder initialization to work. Did you continue reading
more video packets after the first one?


More information about the Libav-user mailing list