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mkvextract: wrong framerate for AV1 video #6120

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opened 2025-06-20 00:18:41 +02:00 by replica9000 · 6 comments

replica9000 commented

2025-06-20 00:18:41 +02:00

When merging a new AV1 encoded file (.ivf), the video plays as expected.
mkvmerge -o file.mkv av1_video.ivf aac_audio.m4a

When extracting the video stream using mkvextract, and merging the video into a new file, the video plays at double speed, while still reporting to be the same framerate as the original. Other streams in the file still play correctly at normal speed.
mkvextract file.mkv tracks 0:av1_video_new.ivf
mkvmerge -o file_new.mkv av1_video_new.ivf aac_audio.m4a

Using the --default-duration option to specify the original framerate doesn't help.

When using ffmpeg to extract the video, the ivf file reports as 1000fps, but using the --default-duration option does correct the speed.

Edit: The videos play double speed in MPV and VLC on Linux. On MX Player for Android, the video is still. The behavior may be different depending on the player.

When merging a new AV1 encoded file (.ivf), the video plays as expected. `mkvmerge -o file.mkv av1_video.ivf aac_audio.m4a` When extracting the video stream using mkvextract, and merging the video into a new file, the video plays at double speed, while still reporting to be the same framerate as the original. Other streams in the file still play correctly at normal speed. `mkvextract file.mkv tracks 0:av1_video_new.ivf` `mkvmerge -o file_new.mkv av1_video_new.ivf aac_audio.m4a` Using the `--default-duration` option to specify the original framerate doesn't help. When using ffmpeg to extract the video, the ivf file reports as 1000fps, but using the `--default-duration` option does correct the speed. Edit: The videos play double speed in MPV and VLC on Linux. On MX Player for Android, the video is still. The behavior may be different depending on the player.

mbunkus added the

app:mkvextract

label

2025-06-22 11:10:47 +02:00

mbunkus commented

2025-06-22 11:12:13 +02:00

Owner

Thanks for reporting it here, too. As I wrote over on Discourse, it'd be helpful to have the original source file a1_video.ivf. Can you please upload it to my file server? Thanks.

Thanks for reporting it here, too. As I wrote over on Discourse, it'd be helpful to have the original source file `a1_video.ivf`. Can you please upload it to my [file server](https://codeberg.org/mbunkus/mkvtoolnix/wiki/FTP-server)? Thanks.

mbunkus added the

other:need-sample

label

2025-06-22 11:12:18 +02:00

replica9000 commented

2025-06-22 15:54:08 +02:00

Author

I uploaded a sample under the folder "Issue #6120"

mbunkus commented

2025-07-27 17:41:50 +02:00

Owner

Arg, I accidentally deleted your uploaded files while cleaning up other uploads. I'm so sorry. Can you please re-upload them? Thanks!

replica9000 commented

2025-07-27 20:33:32 +02:00

Author

No problem. I re-uploaded the files.

mbunkus commented

2025-07-27 20:51:06 +02:00

Owner

Thank you very much!

mbunkus removed the

other:need-sample

label

2025-07-27 20:51:13 +02:00

mbunkus added the

type:bug

label

2025-09-10 20:13:20 +02:00

Khaoklong51 commented

2025-11-05 12:00:47 +01:00

Clip I use to test: https://youtu.be/VHkrLMd5wmA?si=HvGVJ7rsSRMldFY4

ivf file extract with ffmpeg.

command use ffmpeg -i Clip1.mkv -c copy ffmpeg.ivf

try playing ivf files directly (using mpv)
Playback with correct fps.
Mux back to mkv.
2.1 using ffmpeg: Correct playback fps.
2.2 using mkvmerge: 1000 fps sepcified (can be fixed with --default-duration option)

ivf file extract from mkvextract

command use: mkvextract Clip1.mkv tracks 0:mkvextract.ivf

try playing ivf files directly (using mpv)
Playback with wrong fps
Mux back to mkv
2.1 using ffmpeg: Wrong fps playback but correct specifed fps.
2.2 using mkvmerge: Wrong fps playback(double fps of ffmpeg and ivf file) but correct specifed fps.

FFmpeg verrsion:

ffmpeg version 7.1.1-1ubuntu4 Copyright (c) 2000-2025 the FFmpeg developers
  built with gcc 15 (Ubuntu 15.2.0-2ubuntu2)
  configuration: --prefix=/usr --extra-version=1ubuntu4 --toolchain=hardened --libdir=/usr/lib/x86_64-linux-gnu --incdir=/usr/include/x86_64-linux-gnu --arch=amd64 --enable-gpl --disable-stripping --disable-libmfx --disable-omx --enable-gnutls --enable-libaom --enable-libass --enable-libbs2b --enable-libcdio --enable-libcodec2 --enable-libdav1d --enable-libflite --enable-libfontconfig --enable-libfreetype --enable-libfribidi --enable-libglslang --enable-libgme --enable-libgsm --enable-libharfbuzz --enable-libmp3lame --enable-libmysofa --enable-libopenjpeg --enable-libopenmpt --enable-libopus --enable-librubberband --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libtheora --enable-libtwolame --enable-libvidstab --enable-libvorbis --enable-libvpx --enable-libwebp --enable-libx265 --enable-libxml2 --enable-libxvid --enable-libzimg --enable-openal --enable-opencl --enable-opengl --disable-sndio --enable-libvpl --enable-libdc1394 --enable-libdrm --enable-libiec61883 --enable-chromaprint --enable-frei0r --enable-ladspa --enable-libbluray --enable-libcaca --enable-libdvdnav --enable-libdvdread --enable-libjack --enable-libpulse --enable-librabbitmq --enable-librist --enable-libsrt --enable-libssh --enable-libsvtav1 --enable-libx264 --enable-libzmq --enable-libzvbi --enable-lv2 --enable-sdl2 --enable-libplacebo --enable-librav1e --enable-pocketsphinx --enable-librsvg --enable-libjxl --enable-shared
  libavutil      59. 39.100 / 59. 39.100
  libavcodec     61. 19.101 / 61. 19.101
  libavformat    61.  7.100 / 61.  7.100
  libavdevice    61.  3.100 / 61.  3.100
  libavfilter    10.  4.100 / 10.  4.100
  libswscale      8.  3.100 /  8.  3.100
  libswresample   5.  3.100 /  5.  3.100
  libpostproc    58.  3.100 / 58.  3.100

mkvtoolnix version:

mkvmerge v94.0 ('Initiate') 64-bit
mkvextract v94.0 ('Initiate') 64-bit

I think this issue is more serious than I thought it was. At first I thought this only happen to my own encode file, so I decide to grab some random video from youtube download with yt-dlp and the problem still exist. This mean that every av1 bitstream file extract with mkvextract is broken and cannot be fixed with just sepecifying fps at the containner level. Clip I use to test: https://youtu.be/VHkrLMd5wmA?si=HvGVJ7rsSRMldFY4 ## ivf file extract with ffmpeg. command use `ffmpeg -i Clip1.mkv -c copy ffmpeg.ivf` 1. try playing ivf files directly (using mpv) Playback with correct fps. 2. Mux back to mkv. 2.1 using ffmpeg: Correct playback fps. 2.2 using mkvmerge: 1000 fps sepcified (can be fixed with `--default-duration` option) ## ivf file extract from mkvextract command use: `mkvextract Clip1.mkv tracks 0:mkvextract.ivf` 1. try playing ivf files directly (using mpv) Playback with wrong fps 2. Mux back to mkv 2.1 using ffmpeg: Wrong fps playback but correct specifed fps. 2.2 using mkvmerge: Wrong fps playback(double fps of ffmpeg and ivf file) but correct specifed fps. FFmpeg verrsion: ``` ffmpeg version 7.1.1-1ubuntu4 Copyright (c) 2000-2025 the FFmpeg developers built with gcc 15 (Ubuntu 15.2.0-2ubuntu2) configuration: --prefix=/usr --extra-version=1ubuntu4 --toolchain=hardened --libdir=/usr/lib/x86_64-linux-gnu --incdir=/usr/include/x86_64-linux-gnu --arch=amd64 --enable-gpl --disable-stripping --disable-libmfx --disable-omx --enable-gnutls --enable-libaom --enable-libass --enable-libbs2b --enable-libcdio --enable-libcodec2 --enable-libdav1d --enable-libflite --enable-libfontconfig --enable-libfreetype --enable-libfribidi --enable-libglslang --enable-libgme --enable-libgsm --enable-libharfbuzz --enable-libmp3lame --enable-libmysofa --enable-libopenjpeg --enable-libopenmpt --enable-libopus --enable-librubberband --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libtheora --enable-libtwolame --enable-libvidstab --enable-libvorbis --enable-libvpx --enable-libwebp --enable-libx265 --enable-libxml2 --enable-libxvid --enable-libzimg --enable-openal --enable-opencl --enable-opengl --disable-sndio --enable-libvpl --enable-libdc1394 --enable-libdrm --enable-libiec61883 --enable-chromaprint --enable-frei0r --enable-ladspa --enable-libbluray --enable-libcaca --enable-libdvdnav --enable-libdvdread --enable-libjack --enable-libpulse --enable-librabbitmq --enable-librist --enable-libsrt --enable-libssh --enable-libsvtav1 --enable-libx264 --enable-libzmq --enable-libzvbi --enable-lv2 --enable-sdl2 --enable-libplacebo --enable-librav1e --enable-pocketsphinx --enable-librsvg --enable-libjxl --enable-shared libavutil 59. 39.100 / 59. 39.100 libavcodec 61. 19.101 / 61. 19.101 libavformat 61. 7.100 / 61. 7.100 libavdevice 61. 3.100 / 61. 3.100 libavfilter 10. 4.100 / 10. 4.100 libswscale 8. 3.100 / 8. 3.100 libswresample 5. 3.100 / 5. 3.100 libpostproc 58. 3.100 / 58. 3.100 ``` mkvtoolnix version: ``` mkvmerge v94.0 ('Initiate') 64-bit mkvextract v94.0 ('Initiate') 64-bit ```

mbunkus referenced this issue from a commit

2025-11-05 22:35:58 +01:00

mkvextract: AV1/IVF: fix prepending temporal delimiter OBU decision

mbunkus closed this issue

2025-11-05 22:36:02 +01:00

mbunkus referenced this issue from a commit

2025-11-05 22:36:02 +01:00

mkvextract: AV1/IVF: fix type used in file header frame rate calculation

mbunkus referenced this issue from a commit

2025-11-05 22:36:02 +01:00

mkvextract: AV1/IVF: fix IVF frame number calculation by rounding, not truncating

mbunkus referenced this issue from a commit