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Video seeking issues for AV1 encoded files - Printable Version

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Video seeking issues for AV1 encoded files - Doink - 08.10.2025

Hello,

I've started testing the st-av1 codec, but encoded files have seeking issues. In SMPlayer, after starting playback, seeking jumps back to the beginning.
In VLC, audio seeks correct, but video is freezed for 5-10 seconds after that its playing normal. Tested in MKV, MP4, and WEBM containers. For testing
I've encoded the file using Handbrake with the AV1 encoder. No problems for that file. There are no error massages. Will the debug log be useful in this case?

Thx!

RE: Video seeking issues for AV1 encoded files - Selur - 08.10.2025

Does it work in MPC-HC?
Does this only happen with svt-av1? What about other av1 encoders?

Quote:I've encoded the file using Handbrake with the AV1 encoder. No problems for that file.
Assuming you used the same settings for the encoding (with svt-av1), it might be a problem with the muxing,...
If your settings are not the same, the difference in settings might be the cause of the problem.

using latest dev (which comes with updated tools) using svt-av1 I have no problem jumping in https://www.mediafire.com/file/u2sysgdt66vwjca/test.mkv/file

Quote:Will the debug log be useful in this case?
if you hope for help from me: yes
As it shows:
a. your encoding settings
b. the output of svt during encoding
c. the used muxer and the settings during muxing.

Cu Selur

RE: Video seeking issues for AV1 encoded files - Doink - 11.10.2025

Quote:Does it work in MPC-HC?
Does this only happen with svt-av1? What about other av1 encoders?

I will check latter as I don't have easy access to Windows OS.
Interesting, I've encoded same file with aoemnc and there are no seeking issues

Quote:Assuming you used the same settings for the encoding (with svt-av1), it might be a problem with the muxing,...
If your settings are not the same, the difference in settings might be the cause of the problem.

I did not pay particular attention as for the exact settings. Ruffly it was the same
Quote:using latest dev (which comes with updated tools) using svt-av1 I have no problem jumping in https://www.mediafire.com/file/u2sysgdt66vwjca/test.mkv/file

I also don't see seeking issues in this file. Check both in the SMplayer and VLC.
I'm attaching a link to the "broken" file: https://www.mediafire.com/file/5awjtbr8rq82vx8/2025-09-30_21-20-14_-_TEST_CUT_HYBRID_.mkv/file
Also I've sent debug log via PM

RE: Video seeking issues for AV1 encoded files - Selur - 11.10.2025

Muxing was done with ffmpeg:
ffmpeg -y  -r 100/1 -i "/media/pawel/WINDOWS_11/_VIDEO RECODE/2025-10-11@10_42_08_1410_04.av1" -i "/media/pawel/WINDOWS_11/_VIDEO RECODE/iId_1_aid_0_2025-10-11@10_42_08_1410_02.opus" -metadata encoding_tool="Hybrid 2025.07.27.1" -c:v copy -c:1 copy -map 0:0  -map 1:0  -aspect 1920:1080 -r 100/1 "/media/pawel/WINDOWS_11/_VIDEO RECODE/2025-09-30 21-20-14 - TEST CUT_HYBRID_.mkv"
which is not the default, but remuxing with mkvmerge doesn't help so I suspect it's not a muxing problem.

SvtAv1EncApp --input stdin  --width 1920 --height 1080 --fps-num 100 --fps-denom 1 --profile 0 --tile-rows 0 --tile-columns 0 --progress 2 --rc 0 --crf 60 --mbr 5000 --aq-mode 2 --preset 13 --irefresh-type 1 --lookahead 33  --scm 0 --matrix-coefficients 1 --color-range 0 --output "/media/pawel/WINDOWS_11/_VIDEO RECODE/2025-09-30 21-20-14 - TEST CUT_HYBRID__1.av1"
looking at the defaults:
--keyint                     GOP size (frames), default is -2 [-2: ~5 seconds, -1: "infinite" and only applicable for CRF, 0: same as -1]
      --irefresh-type              Intra refresh type, default is 2 [1: FWD Frame (Open GOP), 2: KEY Frame (Closed GOP)]
so svtav1 will create a gop every 5 seconds @100fps this means every 500 frames.

Looking at the content: I suspect the problem is that there are a really few key frames.
What version of SvtAv1EncApp are you using?

Playing the file with ffplay ant trying to seek it reports:
[matroska,webm @ 0000020a0afffa80] seek_frame_generic failed as this stream seems to contain no keyframes after the target timestamp, 1002 non keyframes found

=> try different key frame related settings

Cu Selur

RE: Video seeking issues for AV1 encoded files - Doink - 11.10.2025

SVT-AV1 v3.1.0-rc1-3-gcc569c1e (release). What is strange that if go to config -> tools the app is not listed even after clear cache. I've also copied again whole Hybrid, but still there is no info about this tool.

RE: Video seeking issues for AV1 encoded files - Selur - 12.10.2025

Yeah, I forgot to add it to the list of tools to list.