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threefive-ffmpeg.md

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Two Critical things to remember when using ffmpeg with SCTE-35.

  1. -copyts you need to keep the timestamps if you're transcoding.
  2. -muxpreload 0 -muxdelay 0 needs to be used to keep iframes and SCTE-35 aligned.

threefive works very well with ffmpeg.

  • ffmpeg changes the SCTE-35 (0x86) stream type to bin data (0x6)
  • threefive is the only SCTE35 tool that parses both SCTE-35 (0x86) and bin data (0x6) stream types.
  • __the threefive cli tool can convert the stream_type back to 0x86 after ffmpeg changes it.

Example 1

  • Transcode mpegts with a SCTE-35 stream and pipe it to threefive to parse SCTE-35
    • oldvid.ts looks like this:
  Program 1 
  Stream #0:0[0x31]: Video: h264 (High) ([27][0][0][0] / 0x001B), yuv420p(tv, bt709, progressive), 
  1280x720 [SAR 1:1 DAR 16:9], Closed Captions, 59.94 fps, 59.94 tbr, 90k tbn
  Stream #0:1[0x32]: Audio: mp2 ([4][0][0][0] / 0x0004), 48000 Hz, stereo, s16p, 256 kb/s
  Stream #0:2[0x33]: Audio: mp2 ([4][0][0][0] / 0x0004), 48000 Hz, stereo, s16p, 256 kb/s
  Stream #0:3[0x34]: Audio: mp2 ([4][0][0][0] / 0x0004), 48000 Hz, stereo, s16p, 256 kb/s
  Stream #0:4[0x35]: Audio: mp2 ([4][0][0][0] / 0x0004), 48000 Hz, stereo, s16p, 256 kb/s
  Stream #0:5[0x36]: Data: scte_35
  • transcode
    • -copyts, keep timestamps
    • -map keep SCTE-35 stream
ffmpeg  -copyts -i  oldvid.ts -vcodec libx265  -map 0  -muxpreload 0 -muxdelay 0 -y  newvid.ts
  • newvid.ts looks like this
  Program 1 
  Stream #0:0[0x100]: Video: hevc (Main) (HEVC / 0x43564548), yuv420p(tv, bt709), 1280x720 
  [SAR 1:1 DAR 16:9], 59.94 fps, 59.94 tbr, 90k tbn
  Stream #0:1[0x101]: Audio: mp2 ([3][0][0][0] / 0x0003), 48000 Hz, stereo, fltp, 384 kb/s
  Stream #0:2[0x102]: Audio: mp2 ([3][0][0][0] / 0x0003), 48000 Hz, stereo, fltp, 384 kb/s
  Stream #0:3[0x103]: Audio: mp2 ([3][0][0][0] / 0x0003), 48000 Hz, stereo, fltp, 384 kb/s
  Stream #0:4[0x104]: Audio: mp2 ([3][0][0][0] / 0x0003), 48000 Hz, stereo, fltp, 384 kb/s
  Stream #0:5[0x105]: Data: bin_data ([6][0][0][0] / 0x0006)
  • You can parse it as is with the threefive cli tool
threefive newvid.ts
  • transcode with ffmpeg and pipe into threefive cli as is
ffmpeg  -copyts -i  oldvid.ts -vcodec libx265  -map 0  -muxpreload 0 -muxdelay 0 -f mpegts -| threefive
  • You can also change the stream type from 0x6 back to 0x86 with threefive sixfix so other SCTE-35 parsers can read the SCTE-35.
threefive mpegts sixfix sixed.ts
fixing these pids {258}
Wrote: sixfixed-newvideo.ts