[FFmpeg-user] Transcoding MP4s so that the video starts with Keyframe

[Andrew Sinclair]

You might like to try ffprobe -show_frames on the files you have encoded
and look for an I frame as the first frame. If you see that then the
problem is likely somewhere else.

As Carl says it is unlikely that this issue is with ffmpeg and libx264.


On 3 June 2013 16:36, Tarun singhal <tsinghal18 at gmail.com> wrote:

> >  > How can I transcode MP4 so that it starts with keyframe
> >
> > I don't think it is possible to encode to mp4 with
> > ffmpeg without starting with a keyframe.
> > Please add your failing command line together with
> > the complete, uncut console output.
> >
> > Carl Eugen
> >
> > _______________________________________________
> > ffmpeg-user mailing list
> > ffmpeg-user at ffmpeg.org
> > http://ffmpeg.org/mailman/listinfo/ffmpeg-user
> >
> My objective is to create DASH package using ffmpeg and mp4box in
> conjuction
>  Source file: http://statustreat.com/privatestream/flight_master.mp4<
> http://www.linkedin.com/redirect?url=http%3A%2F%2Fstatustreat%2Ecom%2Fprivatestream%2Fflight_master%2Emp4&urlhash=tyHb&_t=tracking_disc
> >
>
>
>
> 1) ffmpeg -i flight_master.mp4 -f mp4 -r 24 -vcodec libx264 -preset fast
> -profile:v high -an -s 1280x720 -aspect 16:9 -b:v 3000k -map 0:0 -map 0:1
> -b:a 128k -ar 44100 -ac 2 -maxrate 3080k -minrate 2920k -bufsize 6000k
> -acodec aac -strict experimental -x264opts keyint=25:min-keyint=25:sps-id=1
> -keyint_min 25 -g 25 -flags +cgop -sc_threshold 0 -pix_fmt yuv420p -threads
> 0 -y flight_3000.mp4
>
> 2) ffmpeg -i flight_master.mp4 -f mp4 -r 24 -vcodec libx264 -preset fast
> -profile:v high -an -s 640x360 -aspect 16:9 -b:v 1000k -map 0:0 -map 0:1
> -b:a 128k -ar 44100 -ac 2 -maxrate 1080k -minrate 920k -bufsize 2000k
> -acodec aac -strict experimental -x264opts keyint=25:min-keyint=25:sps-id=2
> -keyint_min 25 -g 25 -flags +cgop -sc_threshold 0 -pix_fmt yuv420p -threads
> 0 -y flight_1000.mp4
>
> 3) ffmpeg -i flight_master.mp4 -f mp4 -r 24 -vcodec libx264 -preset fast
> -profile:v high -an -s 320x180 -aspect 16:9 -b:v 600k -map 0:0 -map 0:1
> -b:a 128k -ar 44100 -ac 2 -maxrate 680k -minrate 520k -bufsize 1200k
> -acodec aac -strict experimental -x264opts keyint=25:min-keyint=25:sps-id=3
> -keyint_min 25 -g 25 -flags +cgop -sc_threshold 0 -pix_fmt yuv420p -threads
> 0 -y flight_600.mp4
>
> MP4BOX command: mp4box -dash 20000 -frag 2000 -segment-name flight_test_%s
> -segment-ext mp4 -rap -url-template -out flight.mpd flight_600.mp4
> flight_1000.mp4 flight_3000.mpd
>
> When I played mpd file on chrome browser using DASH player, I get following
> error:
> pipeline_state: kStopped
> url: blob:http%3A//dashif.org/fcca1029-ba6e-430d-ab9d-ca3ed3ff7821
> error: *Media segment did not begin with keyframe. *
> duration: 151.625
> pipeline_error: pipeline: decode error
> seek_target: 0
> *
> *
> *Thanks,*
> *Tarun Singhal*
> _______________________________________________
> ffmpeg-user mailing list
> ffmpeg-user at ffmpeg.org
> http://ffmpeg.org/mailman/listinfo/ffmpeg-user
>