Frame rate control of a ts file

Question

I have a ts file, which is created by encoding raw yuv data using x264enc and muxing it with mpegtsmux.

And this file contains more than one stream. For example it may contain two video streams, or it may contain two video and one text stream like that.

It is of 25 fps, and 720X576 resolution. I would like to change it's fps to say 10, and all the three streams must present in the new ts file also.

Is there any pipeline for this in gstreamer? or any command in ffmpeg? How can i do this?

Answer 1

I don't think that this is possible in GStreamer. At least is not straightforward. However, it should be possible with ffmpeg as long as all the sequences in the file can be discovered correctly.

From the wiki of ffmpeg, map option (https://trac.ffmpeg.org/wiki/Map):

The "map" command basically means "include this stream into the immediately following OUTPUT file."

Using map option it is possible to re-encode the video stream that you want and keep untouched the others.

Using input.ts file as an example with 2 different video streams and some audio streams, the way to follow should be the next:

ffmpeg -i input.ts -map 0:0 -map 0:2 -map 0:3 -map 0:4 -map 0:23 -map 0:10 -map 0:14 -c:v:0 mpeg2video -r:v:0 10 -c:v:1 copy -c:a copy outputmini.ts

Note that the video streams are 0:0 and 0:23. The first video stream (mpeg2) is re-encoded to 10 fps whereas the 0:23 video stream (x264) is just copied to the output. Remember that if there is some unknown stream in the .ts file you may need to add -ignore_unknown flag.

As specified in the link from ffmpeg, the output stream order is specified in the command execution in the map option placement order. With -c:v:0 mpeg2video option, we select the first output video stream and re-encoding codec, while the -r:v:0 10 option puts the first video stream frame rate to 10 fps. The other options from the command line copies the input stream to output with the same parameters.

ffmpeg outputs next:

Output #0, mpegts, to 'outputmini.ts':
  Metadata:
    encoder         : Lavf57.41.100
    Stream #0:0: Video: mpeg2video (Main), yuv420p, 640x576 [SAR 6:5 DAR 4:3], q=2-31, 200 kb/s, 10 fps, 90k tbn, 10 tbc
    Metadata:
      encoder         : Lavc57.50.100 mpeg2video
    Side data:
      cpb: bitrate max/min/avg: 0/0/200000 buffer size: 0 vbv_delay: -1
    Stream #0:1(spa): Audio: mp2 ([3][0][0][0] / 0x0003), 48000 Hz, stereo, 192 kb/s
    Stream #0:2(qaa): Audio: mp2 ([3][0][0][0] / 0x0003), 48000 Hz, stereo, 192 kb/s
    Stream #0:3(spa): Audio: mp2 ([3][0][0][0] / 0x0003), 48000 Hz, mono, 96 kb/s (visual impaired)
    Stream #0:4: Video: h264 ([27][0][0][0] / 0x001B), yuv420p(tv, bt709), 1280x720 [SAR 1:1 DAR 16:9], q=2-31, 50 fps, 50 tbr, 90k tbn, 90k tbc
    Stream #0:5(spa): Audio: eac3 ([6][0][0][0] / 0x0006), 48000 Hz, stereo, 256 kb/s
    Stream #0:6(spa): Audio: eac3 ([6][0][0][0] / 0x0006), 48000 Hz, mono, 64 kb/s (visual impaired)
Stream mapping:
  Stream #0:0 -> #0:0 (mpeg2video (native) -> mpeg2video (native))
  Stream #0:2 -> #0:1 (copy)
  Stream #0:3 -> #0:2 (copy)
  Stream #0:4 -> #0:3 (copy)
  Stream #0:23 -> #0:4 (copy)
  Stream #0:10 -> #0:5 (copy)
  Stream #0:14 -> #0:6 (copy)

The desired output is achieved.

However, even though I'm not sure this could be done, I would get a glimpse to tsMuxeR appllication (http://www.videohelp.com/software/tsMuxeR). It is a very powerful tool to this kind of tasks.