[Libav-user] mpeg4 encoding with no b-frames

Alex Cohn alexcohn at netvision.net.il
Fri Oct 18 00:15:17 CEST 2013

The ffmpeg mpeg4 encoder was designed to preserve b-frames as in
input. It warns you that these frames will be rearranged. It's just a

Alex Cohn

On Thu, Oct 17, 2013 at 11:42 AM, marcin_ffmpeg
<marcin_ffmpeg at interia.pl> wrote:
> Dear All
> In my application I'm trying to re-encode video from h264 to mpeg4. It is important to have no b-frames in the output file so I set
> encoder context to max_b_frames=0, gop_size is fixed to 25.
> With this setting I get loads of following warnings
> [mpeg4 @ 0xa53f3620] warning, too many b frames in a row
> Problem does not exists when encoder gop_size is set to decoder gop_size and max_b_frames is set to 10.
> Is there something what can be done about that? Does frame after decoding from h264 have to be somehow converted?
> Thanks for any help
> Marcin
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