[FFmpeg-user] Getting H264 elementary stream from mp4

[Francois Visagie]

I experience the same accelerated playback, both with elementary
streams demuxed by ffmpeg as well as x264 itself.

Something else I noticed in the output file in both cases is that its
frame rate gets set to variable, although that patently wasn't the
case for input files I tested with, and there were no command line
options influencing frame rate.

In the case of x264, the --fps <framerate> option seems to solve the
problem, with <framerate> set to that of the input file. I haven't
tested with ffmpeg.

On 30 October 2014 13:32, Shashank Pathak
<shashank.pathak at einfochips.com> wrote:
> Hi All,
>
> We are having one mp4 file with h264 codec.
> we want to feed this file to a video decoder but the decoder requires
> elementary stream.
> So we tried to extract H264 elementary string from mp4 with below ffmpeg
> commnd,
>
> ffmpeg -i input.mp4 -vcodec copy -vbsf h264_mp4toannexb output.h264
>
> Now with this command we are getting h264 file but this file is not having
> I-frame in it.
> We viewed the file in Hex editor and found that it contains,
> 00 00 00 01 67 --> SPS frame
> 00 00 00 01 68 --> PPS frame
> But we couldn't find,
> 00 00 00 01 65 --> I-frmae.
>
> VLC is not able to play the generated h264 file.
> ffplay plays the file but very fast (higher fps).
>
> Can anyone suggest what we are doing wrong?
> or Any other method to get H264 file?
>
> --
> Best Regards,
> Shashank Pathak
> Senior Engineer | PES
>
> [cid:part1.05050907.05040709 at einfochips.com]
> Product Engineering Services
> Software | Embedded | Semiconductor
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