[Libav-user] FFMPEG Ported to iOS and Use Segment Function

[Stefano Sabatini]

On date Monday 2013-12-02 10:36:58 +0800, Krissa Carbon encoded:
> Good day.
> 
> I have been trying to implement a video segmenter in objective-c for an
> application on iPhone. I see that the ffmpeg has all the things I need such
> as encoders when used in a terminal of a pc.
> 
> I have already ported the ffmpeg codes to be used in iOS. I would like to
> ask if you can give me tips on how can I trace the encoding and
> segmentation process in the ffmpeg code so I can mimic this process in iOS.
> 
> the command I use to encode and segment my file using mac terminal is:
> 
> ffmpeg -i <video-file> -vcodec libx264 -acodec libfaac -r 29.97 -profile:v
> baseline -b:v 2048k -maxrate 2048k -minrate 2048k -bufsize 2048k
> -force_key_frames 'expr:gte(t,n_forced*1)' -map 0 -flags -global_header -f
> segment -segment_list index.m3u8 -segment_time 1 -segment_format mpeg_ts
> -segment_list_type m3u8 segment%05d.ts
> 
> or
> 
> ffmpeg -i <video-file>  -c copy -bsf h264_mp4toannexb -r 29.97 -profile:v
> baseline -b:v 2048k -maxrate 2048k -minrate 2048k -bufsize 2048k
> -force_key_frames 'expr:gte(t,n_forced*1)' -map 0 -flags -global_header -f
> segment -segment_list index.m3u8 -segment_time 1 -segment_format mpeg_ts
> -segment_list_type m3u8 segment%05d.ts

All the segmenter relevant code is in libavformat/segment.c, and it's
relatively simple. -force_key_frames is implemented in ffmpeg.c, but
you can easily emulate the behavior forcing the key_frame flag in the
frame passed to the encoder according to custom application logic.

Note that if you are using libavformat, you can directly use the
segment muxer.