mpv+ffmpeg warnings: [ffmpeg/video] h264: Late SEI is not implemented

grobber · 2025-11-30 15:38:46

Recently, I have started to see warnings (displayed in yellow in whichever terminal session started mpv) when playing certain mp4 videos (not all). One example is this 1-minute snippet (the link takes you to a downloadable 2.1M mp4 hosted in a Dropbox folder).

Simply running

mpv <file>

will produce this warning every second or so for as long as the video is playing:

[ffmpeg/video] h264: Late SEI is not implemented. Update your FFmpeg version to the newest one from Git. If the problem still occurs, it means that your file has a feature which has not been implemented.
[ffmpeg/video] h264: If you want to help, upload a sample of this file to https://streams.videolan.org/upload/ and contact the ffmpeg-devel mailing list. (ffmpeg-devel@ffmpeg.org)

Last edited by grobber (2025-11-30 15:40:52)

teckk · 2025-11-30 21:41:56

url="https://www.dropbox.com/scl/fi/n1oa7qih144ndvqfkdcgx/dp-01-09-17-leaked-call-exposes-trump-as-approval-craters-republicans-raise-alarm-112625-tdps-podcast_out.mp4?rlkey=miwey4h3rr2bxrokh79js2xue&e=1&dl=0"

mpv "$url"
...
[ffmpeg/demuxer] mpegts: Packet corrupt (stream = 0, dts = 357357).
[ffmpeg/demuxer] hls: Packet corrupt (stream = 0, dts = 354354).
[ffmpeg/demuxer] mpegts: Packet corrupt (stream = 0, dts = 717717).
[ffmpeg/demuxer] hls: Packet corrupt (stream = 0, dts = 714714).
[ffmpeg/demuxer] mpegts: Packet corrupt (stream = 0, dts = 1078077).
...

Looks like transport stream segments that are not synced to the timebase.

It is separate audio/video streams.

yt-dlp -F "$url"
...
[info] Available formats for n1oa7qih144ndvqfkdcgx:
ID              EXT RESOLUTION FPS │  TBR PROTO │ VCODEC       VBR ACODEC     MORE INFO
───────────────────────────────────────────────────────────────────────────────────────────
aud128k-Track_1 mp4 audio only     │      m3u8  │ audio only       unknown    [eng] Track 1
360p            mp4 640x360     30 │ 272k m3u8  │ avc1.42001E 272k video only
original        mp4 unknown        │      https │ unknown          unknown    Original

yt-dlp -f 360p+aud128k-Track_1 "$url" -o - | mpv -
...
AO: [alsa] 48000Hz stereo 2ch float
VO: [gpu] 640x360 yuv420p
AV: 00:00:00 / 00:00:03 (0%) A-V:  0.000 Cache: 3.6s/311KB[mpegts @ 0x559f5d392080] Packet corrupt (stream = 0, dts = 357357).
[hls @ 0x559f5cbc93c0] Packet corrupt (stream = 0, dts = 354354).
[in#0/hls @ 0x559f5cbc9100] corrupt input packet in stream 0

Looks like a crap video to me.

seth · 2025-11-30 22:12:12

The video on youtube

mpv 'https://www.youtube.com/watch?v=7GcyNif6PM8'

has the same, so either DP or google fudged it.
Where else have you seen this? Anything not from that channel?

grobber · 2025-11-30 22:24:09

Thanks!

To answer in chronological order, RE: the corrupt packets: yes, I am getting those too on my own Dropbox link, but not on the original youtube source:

mpv 'https://www.youtube.com/watch?v=7GcyNif6PM8'

produces no complaints. The video was indeed originally downloaded with yt-dlp, quality -f 18 (I am usually content with that).

RE: other instances of the issue: yes, on this youtube video (still youtube, different channel), also when downloading an mp4 with yt-dlp -f 18. I will try to recall others, but these parameters apply to all instances I have encountered:

downloaded from youtube with yt-dlp
with quality -f 18:

yt-dlp -f 18 <URL>

Last edited by grobber (2025-11-30 22:25:28)

seth · 2025-11-30 22:35:26

◉ mpv --ytdl-raw-options="format=18" 'https://www.youtube.com/watch?v=7GcyNif6PM8'                    
● Video  --vid=1                     (h264 640x360 29.97 fps) [default]
● Audio  --aid=1  --alang=eng        (aac 2ch 44100 Hz 48 kbps) [default]
○ Subs   --sid=1  --slang=live_chat  'json' (null) [external]
File tags:
 Date: 20251127
 Uploader: David Pakman Show
 Channel_URL: https://www.youtube.com/channel/UCvixJtaXuNdMPUGdOPcY8Ag
[ffmpeg/video] h264: Late SEI is not implemented. Update your FFmpeg version to the newest one from Git. If the problem still occurs, it means that your file has a feature which has not been implemented.
[ffmpeg/video] h264: If you want to help, upload a sample of this file to https://streams.videolan.org/upload/ and contact the ffmpeg-devel mailing list. (ffmpeg-devel@ffmpeg.org)
AO: [alsa] 48000Hz stereo 2ch float
VO: [gpu] 640x360 yuv420p
[ffmpeg/video] h264: Late SEI is not implemented. Update your FFmpeg version to the newest one from Git. If the problem still occurs, it means that your file has a feature which has not been implemented.
[ffmpeg/video] h264: If you want to help, upload a sample of this file to https://streams.videolan.org/upload/ and contact the ffmpeg-devel mailing list. (ffmpeg-devel@ffmpeg.org)
[ffmpeg/video] h264: Late SEI is not implemented. Update your FFmpeg version to the newest one from Git. If the problem still occurs, it means that your file has a feature which has not been implemented.
[ffmpeg/video] h264: If you want to help, upload a sample of this file to https://streams.videolan.org/upload/ and contact the ffmpeg-devel mailing list. (ffmpeg-devel@ffmpeg.org)
AV: 00:00:10 / 01:09:16 (0%) A-V:  0.000 Cache: 300s/19MB
Exiting... (Quit)

mpv --ytdl-raw-options="format=18" 'https://www.youtube.com/watch?v=g0TRjDBduLY'                    
● Video  --vid=1               (h264 640x360 29.97 fps) [default]
● Audio  --aid=1  --alang=eng  (aac 2ch 44100 Hz 48 kbps) [default]
File tags:
 Date: 20251128
 Uploader: Professor Dave Explains
 Channel_URL: https://www.youtube.com/channel/UC0cd_-e49hZpWLH3UIwoWRA
[ffmpeg/video] h264: Late SEI is not implemented. Update your FFmpeg version to the newest one from Git. If the problem still occurs, it means that your file has a feature which has not been implemented.
[ffmpeg/video] h264: If you want to help, upload a sample of this file to https://streams.videolan.org/upload/ and contact the ffmpeg-devel mailing list. (ffmpeg-devel@ffmpeg.org)
AO: [alsa] 48000Hz stereo 2ch float
VO: [gpu] 640x360 yuv420p
[ffmpeg/video] h264: Late SEI is not implemented. Update your FFmpeg version to the newest one from Git. If the problem still occurs, it means that your file has a feature which has not been implemented.
[ffmpeg/video] h264: If you want to help, upload a sample of this file to https://streams.videolan.org/upload/ and contact the ffmpeg-devel mailing list. (ffmpeg-devel@ffmpeg.org)
AV: 00:00:08 / 01:34:47 (0%) A-V:  0.000 Cache: 300s/18MB
Exiting... (Quit)

mpv --ytdl-raw-options="format=18" 'https://www.youtube.com/watch?v=WZVvCuo63Bw'                    
● Video  --vid=1               (h264 640x360 30 fps) [default]
● Audio  --aid=1  --alang=eng  (aac 2ch 44100 Hz 96 kbps) [default]
○ Subs   --sid=1  --slang=en   'English' (null) [external]
File tags:
 Date: 20251130
 Uploader: CNN
 Channel_URL: https://www.youtube.com/channel/UCupvZG-5ko_eiXAupbDfxWw
AO: [alsa] 48000Hz stereo 2ch float
VO: [gpu] 640x360 yuv420p
AV: 00:00:12 / 00:10:38 (2%) A-V:  0.000 Cache: 300s/24MB
Exiting... (Quit)

◉ mpv --ytdl-raw-options="format=18" 'https://www.youtube.com/watch?v=N1FhFzamDsY'                    
● Video  --vid=1               (h264 640x360 29.97 fps) [default]
● Audio  --aid=1  --alang=eng  (aac 2ch 44100 Hz 48 kbps) [default]
File tags:
 Date: 20251125
 Uploader: Skate IQ
 Channel_URL: https://www.youtube.com/channel/UC-Pk-TTaSrDOjkPKQ7C8HXQ
[ffmpeg/video] h264: Late SEI is not implemented. Update your FFmpeg version to the newest one from Git. If the problem still occurs, it means that your file has a feature which has not been implemented.
[ffmpeg/video] h264: If you want to help, upload a sample of this file to https://streams.videolan.org/upload/ and contact the ffmpeg-devel mailing list. (ffmpeg-devel@ffmpeg.org)
AO: [alsa] 48000Hz stereo 2ch float
VO: [gpu] 640x360 yuv420p
AV: 00:00:05 / 00:31:55 (0%) A-V:  0.000 Cache: 300s/22MB

Seems to be the 29.97 fps videos.

teckk · 2025-12-01 02:35:23

[ffmpeg/video] h264: If you want to help, upload a sample of this file to https://streams.videolan.org/upload/ and contact the ffmpeg-devel mailing list. (ffmpeg-devel@ffmpeg.org)

If the OP wants to.

url=$(yt-dlp -f 18 -g https://www.youtube.com/watch?v=7GcyNif6PM8)

ffmpeg -t 00:01:00 -i "$url" -c:a copy -c:v copy test1.mp4

teckk · 2025-12-01 02:44:26

By the way. 136 which is x264/aac just larger is ok.

yt-dlp -f 136+140 https://www.youtube.com/watch?v=7GcyNif6PM8 -o - | ffplay -

And 18 is 640x360 x264/aac, so separate streams...

yt-dlp -f 134+140 https://www.youtube.com/watch?v=7GcyNif6PM8 -o - | ffplay -

Is ok also, no errors.

seth · 2025-12-01 08:23:52

◉ mpv --ytdl-raw-options="format=136+140" 'https://www.youtube.com/watch?v=7GcyNif6PM8'   09:17 [5/1872]
                                                                                                                                
● Video  --vid=1                     (h264 1280x720 29.97 fps) [default]                                                        
● Audio  --aid=1  --alang=eng        (aac 2ch 44100 Hz 128 kbps) [default]                                                      
○ Subs   --sid=1  --slang=live_chat  'json' (null) [external]                                                                   
File tags:                                                                                                                      
 Date: 20251127
 Uploader: David Pakman Show
 Channel_URL: https://www.youtube.com/channel/UCvixJtaXuNdMPUGdOPcY8Ag
[ffmpeg/video] h264: Late SEI is not implemented. Update your FFmpeg version to the newest one from Git. If the problem still occurs, it means that your file has a feature which has not been implemented.
[ffmpeg/video] h264: If you want to help, upload a sample of this file to https://streams.videolan.org/upload/ and contact the ffmpeg-devel mailing list. (ffmpeg-devel@ffmpeg.org)
AO: [alsa] 48000Hz stereo 2ch float
VO: [gpu] 1280x720 yuv420p

same for 134 - piping yt-dlp into ffplay is different since it (seems to) downloads the entire streams first.

nb. that 140 might get you into trouble because of this GOD DAMN AWFUL HORRIFIC autotranslation (ie. you'd need 140-n and the "n" for the original stream isn't a stable index), try "m4a[format_note~=original]" instead

grobber · 2025-12-01 12:29:11

Thanks!

It sounds like there's nothing for it but to report to ffmpeg (so not really an Arch issue). I don't mind doing that, but would we call this solved then? If you think so, I'll be happy to change the title to reflect this.

seth · 2025-12-01 16:18:50

There isn't much we can do here, you can keep the thread open until there's some upstream comment (only ntsc being affected by 30fps not makes me wonder whether this is a youtube problem, have you seen it elsewhere?)

grobber · 2025-12-01 16:57:04

Sounds good, will keep it open until there's engagement from ffmpeg-devel@ffmpeg.org (my message is currently in moderation there).

I do not know whether the problem manifests off youtube; I have not tried elsewhere.

seth · 2025-12-01 20:46:25

Do you get this w/ "mpv --hwdec=vaapi"?
I just noticed I've been decoding in software and it's not showing up w/ vaapi

You might need the proper driver, see https://wiki.archlinux.org/title/Hardwa … stallation

grobber · 2025-12-01 21:20:46

Same behavior as you report:

mpv --hwdec=vaapi <VIDEO>

does not produce the warning (did not need any extra installs; intel-media-driver suffices on this machine, and I had it).

Arch Linux

#1 2025-11-30 15:38:46

mpv+ffmpeg warnings: [ffmpeg/video] h264: Late SEI is not implemented

#2 2025-11-30 21:41:56

Re: mpv+ffmpeg warnings: [ffmpeg/video] h264: Late SEI is not implemented

#3 2025-11-30 22:12:12

Re: mpv+ffmpeg warnings: [ffmpeg/video] h264: Late SEI is not implemented

#4 2025-11-30 22:24:09

Re: mpv+ffmpeg warnings: [ffmpeg/video] h264: Late SEI is not implemented

#5 2025-11-30 22:35:26

Re: mpv+ffmpeg warnings: [ffmpeg/video] h264: Late SEI is not implemented

#6 2025-12-01 02:35:23

Re: mpv+ffmpeg warnings: [ffmpeg/video] h264: Late SEI is not implemented

#7 2025-12-01 02:44:26

Re: mpv+ffmpeg warnings: [ffmpeg/video] h264: Late SEI is not implemented

#8 2025-12-01 08:23:52

Re: mpv+ffmpeg warnings: [ffmpeg/video] h264: Late SEI is not implemented

#9 2025-12-01 12:29:11

Re: mpv+ffmpeg warnings: [ffmpeg/video] h264: Late SEI is not implemented

#10 2025-12-01 16:18:50

Re: mpv+ffmpeg warnings: [ffmpeg/video] h264: Late SEI is not implemented

#11 2025-12-01 16:57:04

Re: mpv+ffmpeg warnings: [ffmpeg/video] h264: Late SEI is not implemented

#12 2025-12-01 20:46:25

Re: mpv+ffmpeg warnings: [ffmpeg/video] h264: Late SEI is not implemented

#13 2025-12-01 21:20:46

Re: mpv+ffmpeg warnings: [ffmpeg/video] h264: Late SEI is not implemented

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