[FFmpeg-user] Using ffmpeg with youtube-dl: Non-monotonous DTS in output stream

[Gyan]

On 15-12-2018 07:15 AM, Tefl Zuren wrote:
> I'm trying to download a video with youtube-dl (http://rg3.github.io/youtube-dl/). It uses ffmpeg. At the beginning of the second group of mpegts files, ffmpeg starts throwing the error "Non-monotonous DTS in output stream 0:0; ... This may result in incorrect timestamps in the output file." and continues for the remainder of the download. The saved mp4 file is only playable up to 20:26 then it freezes. This problem usually occurs only on the TNT and TBS websites. The output is:
> [hls,applehttp @ 0x23c7900] Opening 'https://tve.cdn.turner.com/tnt/83b278d50b415d38d9d85e6584e23004/layer7/seg.key' for reading
> [hls,applehttp @ 0x23c7900] Opening 'crypto+https://tve.cdn.turner.com/tnt/83b278d50b415d38d9d85e6584e23004/layer7/seg-0_00000.ts' for reading
> Input #0, hls,applehttp, from 'https://tve.cdn.turner.com/tnt/83b278d50b415d38d9d85e6584e23004/layer7/layer7_bk.m3u8?hdntl=exp=1544853868~acl=%2ftnt%2f83b278d50b415d38d9d85e6584e23004%2f*~hmac=421213acd762b1be021249cc78935d1141e301a3b8f31e73318c0131dc384093':
>    Duration: 01:29:01.24, start: 1.466733, bitrate: 0 kb/s
>    Program 0
>      Metadata:
>        variant_bitrate : 0
>      Stream #0:0: Video: h264 (High) ([27][0][0][0] / 0x001B), yuv420p, 1920x1080 [SAR 1:1 DAR 16:9], Closed Captions, 29.97 fps, 29.97 tbr, 90k tbn, 59.94 tbc
>      Metadata:
>        variant_bitrate : 0
>      Stream #0:1: Audio: aac (LC) ([15][0][0][0] / 0x000F), 44100 Hz, stereo, fltp
>      Metadata:
>        variant_bitrate : 0

> [hls,applehttp @ 0x23c7900] Opening 'crypto+https://tve.cdn.turner.com/tnt/83b278d50b415d38d9d85e6584e23004/layer7/seg-0_00001.ts' for reading
> ...
> [hls,applehttp @ 0x23c7900] Opening 'crypto+https://tve.cdn.turner.com/tnt/83b278d50b415d38d9d85e6584e23004/layer7/seg-0_00204.ts' for reading
> [hls,applehttp @ 0x23c7900] Opening 'crypto+https://tve.cdn.turner.com/tnt/83b278d50b415d38d9d85e6584e23004/layer7/seg-1_00000.ts' for reading
> [mp4 @ 0x2479700] Non-monotonous DTS in output stream 0:0; previous: 110426426, current: -6006; changing to 110426427. This may result in incorrect timestamps in the output file.
> [mp4 @ 0x2479700] Non-monotonous DTS in output stream 0:0; previous: 110426427, current: -3003; changing to 110426428. This may result in incorrect timestamps in the output file.
> [mp4 @ 0x2479700] Non-monotonous DTS in output stream 0:0; previous: 110426428, current: 0; changing to 110426429. This may result in incorrect timestamps in the output file.
> [mp4 @ 0x2479700] Non-monotonous DTS in output stream 0:0; previous: 110426429, current: 3003; changing to 110426430. This may result in incorrect timestamps in the output file.
> [mp4 @ 0x2479700] Non-monotonous DTS in output stream 0:0; previous: 110426430, current: 6006; changing to 110426431. This may result in incorrect timestamps in the output file.

Some playlists contain a sequence of separately produced MPEG-TS files. 
So, there's a timestamp reset when each new segment is received. At this 
point, the timestamp code in libavformat's mux.c simply increments the 
output timestamp by one when this happens. Unless the timebase 
resolution is 1/fps, this produces an unsound file. Workaround is to 
extract the individual streams and remux using mp4box.

     ffmpeg -i downloaded.mp4 -c copy video.h264

     ffmpeg -i downloaded.mp4 -c copy audio.aac

     mp4box -add video.h264 -add audio.aac -new fixed.mp4


Gyan