Referenced QT chapter track not found

[Code-With-Samuel]

I was wondering if i can use this project for videos with any extensions. The .mp4 extension worked well but when i tried with the .mov extension, it gave this :

(.venv) D:\ayush.khanal\video-kf>video-kf "abc.mov"
[mov,mp4,m4a,3gp,3g2,mj2 @ 000001a8e70a8640] Referenced QT chapter track not found

FYI: "pip install video-kf" is already performed in the virtual environment. Also my keyframe folder is completely empty incase if it needs to be.

If its the limitation with the source code or if I'm missing something out, please let me know.

[averdones]

Hey. This is a very old project that I haven't touched in years, but I think it should work with .mov files too, as it uses ffmpeg directly. That message is a warning from ffmpeg, not an error, telling you that some data within the file is missing. So, perhaps there is an issue with the file?

You could try remuxing the file with something like this:

ffmpeg -i "abc.mov" -c copy -map_chapters -1 "abc_fixed.mov"

[Code-With-Samuel]

PS D:\ayush.khanal\video-kf> .venv\Scripts\activate
(.venv) PS D:\ayush.khanal\video-kf> ffmpeg -i "abc.mov" -c copy -map_chapters -1 "abc_fixed.mov"
ffmpeg version 8.0.1-full_build-www.gyan.dev Copyright (c) 2000-2025 the FFmpeg developers
built with gcc 15.2.0 (Rev8, Built by MSYS2 project)
configuration: --enable-gpl --enable-version3 --enable-static --disable-w32threads --disable-autodetect --enable-fontconfig --enable-iconv --enable-gnutls --enable-lcms2 --enable-libxml2 --enable-gmp --enable-bzlib --enable-lzma --enable-libsnappy --enable-zlib --enable-librist --enable-libsrt --enable-libssh --enable-libzmq --enable-avisynth --enable-libbluray --enable-libcaca --enable-libdvdnav --enable-libdvdread --enable-sdl2 --enable-libaribb24 --enable-libaribcaption --enable-libdav1d --enable-libdavs2 --enable-libopenjpeg --enable-libquirc --enable-libuavs3d --enable-libxevd --enable-libzvbi --enable-liboapv --enable-libqrencode --enable-librav1e --enable-libsvtav1 --enable-libvvenc --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxavs2 --enable-libxeve --enable-libxvid --enable-libaom --enable-libjxl --enable-libvpx --enable-mediafoundation --enable-libass --enable-frei0r --enable-libfreetype --enable-libfribidi --enable-libharfbuzz --enable-liblensfun --enable-libvidstab --enable-libvmaf --enable-libzimg --enable-amf --enable-cuda-llvm --enable-cuvid --enable-dxva2 --enable-d3d11va --enable-d3d12va --enable-ffnvcodec --enable-libvpl --enable-nvdec --enable-nvenc --enable-vaapi --enable-libshaderc --enable-vulkan --enable-libplacebo --enable-opencl --enable-libcdio --enable-openal --enable-libgme --enable-libmodplug --enable-libopenmpt --enable-libopencore-amrwb --enable-libmp3lame --enable-libshine --enable-libtheora --enable-libtwolame --enable-libvo-amrwbenc --enable-libcodec2 --enable-libilbc --enable-libgsm --enable-liblc3 --enable-libopencore-amrnb --enable-libopus --enable-libspeex --enable-libvorbis --enable-ladspa --enable-libbs2b --enable-libflite --enable-libmysofa --enable-librubberband --enable-libsoxr --enable-chromaprint --enable-whisper
libavutil 60. 8.100 / 60. 8.100
libavcodec 62. 11.100 / 62. 11.100
libavformat 62. 3.100 / 62. 3.100
libavdevice 62. 1.100 / 62. 1.100
libavfilter 11. 4.100 / 11. 4.100
libswscale 9. 1.100 / 9. 1.100
libswresample 6. 1.100 / 6. 1.100
[mov,mp4,m4a,3gp,3g2,mj2 @ 0000016a23b655c0] Referenced QT chapter track not found
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'abc.mov':
Metadata:
major_brand : qt
minor_version : 537199360
compatible_brands: qt
creation_time : 2025-09-15T07:56:11.000000Z
Duration: 00:13:43.25, start: 0.000000, bitrate: 143894 kb/s
Stream #0:00x1: Video: prores (HQ) (apch / 0x68637061), yuv422p10le(bt709, progressive), 1920x1080, 142326 kb/s, SAR 1:1 DAR 16:9, 24 fps, 24 tbr, 24 tbn (default)
Metadata:
creation_time : 2025-09-15T07:56:11.000000Z
handler_name : Apple Video Media Handler
vendor_id : appl
encoder : Apple ProRes 422 HQ
timecode : 00:00:00:00
Stream #0:10x2: Audio: pcm_s16le (sowt / 0x74776F73), 48000 Hz, stereo, s16, 1536 kb/s (default)
Metadata:
creation_time : 2025-09-15T07:56:11.000000Z
handler_name : Apple Sound Media Handler
vendor_id :
timecode : 00:00:00:00
Stream #0:20x3: Data: none (tmcd / 0x64636D74) (default)
Metadata:
creation_time : 2025-09-15T07:56:11.000000Z
handler_name : Time Code Media Handler
timecode : 00:00:00:00
Stream mapping:
Stream #0:0 -> #0:0 (copy)
Stream #0:1 -> #0:1 (copy)
Output #0, mov, to 'abc_fixed.mov':
Metadata:
major_brand : qt
minor_version : 537199360
compatible_brands: qt
encoder : Lavf62.3.100
Stream #0:0(eng): Video: prores (HQ) (apch / 0x68637061), yuv422p10le(bt709, progressive), 1920x1080 [SAR 1:1 DAR 16:9], q=2-31, 142326 kb/s, 24 fps, 24 tbr, 12288 tbn (default)
Metadata:
creation_time : 2025-09-15T07:56:11.000000Z
handler_name : Apple Video Media Handler
vendor_id : appl
encoder : Apple ProRes 422 HQ
timecode : 00:00:00:00
Stream #0:1(eng): Audio: pcm_s16le (sowt / 0x74776F73), 48000 Hz, stereo, s16, 1536 kb/s (default)
Metadata:
creation_time : 2025-09-15T07:56:11.000000Z
handler_name : Apple Sound Media Handler
vendor_id :
timecode : 00:00:00:00
Press [q] to stop, [?] for help
[out#0/mov @ 0000016a23b6db00] video:14302976KiB audio:154359KiB subtitle:0KiB other streams:0KiB global headers:0KiB muxing overhead: 0.002949%
frame=19758 fps= 91 q=-1.0 Lsize=14457762KiB time=00:13:43.25 bitrate=143866.4kbits/s speed=3.78x elapsed=0:03:37.65
(.venv) PS D:\ayush.khanal\video-kf> video-kf "abc_fixed.mov" -o keyframes_3
Downloading frames ...
Traceback (most recent call last):
File "C:\Users\ayush.khanal\AppData\Local\Programs\Python\Python310\lib\runpy.py", line 196, in _run_module_as_main
return _run_code(code, main_globals, None,
File "C:\Users\ayush.khanal\AppData\Local\Programs\Python\Python310\lib\runpy.py", line 86, in run_code
exec(code, run_globals)
File "D:\ayush.khanal\video-kf.venv\Scripts\video-kf.exe_main.py", line 7, in
File "D:\ayush.khanal\video-kf.venv\lib\site-packages\videokf\cli_scripts.py", line 26, in main
extract_keyframes(args.video_file, args.method, args.output_dir_keyframes, args.dir_ffmpeg_ffprobe, args.ffmpeg,
File "D:\ayush.khanal\video-kf.venv\lib\site-packages\videokf\extract_keyframes.py", line 34, in extract_keyframes
get_keyframes(ffmpeg_exe, ffprobe_exe, video_file, method, output_dir_keyframes, remove_frames_dir)
File "D:\ayush.khanal\video-kf.venv\lib\site-packages\videokf\keyframe_manager\keyframe_extractor.py", line 52, in get_keyframes
extract_frames(ffmpeg_exe, video_file, frames_selected=iframes, output_dir=output_dir, frame_type=method)
File "D:\ayush.khanal\video-kf.venv\lib\site-packages\videokf\utils\vidutils.py", line 52, in extract_frames
subprocess.check_output(ffmpeg_args)
File "C:\Users\ayush.khanal\AppData\Local\Programs\Python\Python310\lib\subprocess.py", line 420, in check_output
return run(*popenargs, stdout=PIPE, timeout=timeout, check=True,
File "C:\Users\ayush.khanal\AppData\Local\Programs\Python\Python310\lib\subprocess.py", line 501, in run
with Popen(*popenargs, **kwargs) as process:
File "C:\Users\ayush.khanal\AppData\Local\Programs\Python\Python310\lib\subprocess.py", line 969, in init
self._execute_child(args, executable, preexec_fn, close_fds,
File "C:\Users\ayush.khanal\AppData\Local\Programs\Python\Python310\lib\subprocess.py", line 1438, in _execute_child
hp, ht, pid, tid = _winapi.CreateProcess(executable, args,
FileNotFoundError: [WinError 206] The filename or extension is too long
(.venv) PS D:\ayush.khanal\video-kf>

[Code-With-Samuel]

This is what i came up with. Any idea on what the issue is or how can it be solved?

[averdones]

I haven't tested this, but I might know what is happening.

Your video is ProRes 422 HQ, an intra-frame (All-I) codec. This means every single frame is an I-frame (i.e.: a keyframe). Your video has 19,758 frames. My program, by default, will try to extract every single frame of the video by creating a list of strings with 19,758 elements in the function make_frames_list. This will then be passed to the command line which will results in an Error because Windows doesn't accept such a long string.

Regardless of the error, you don't probably want to extract every frame in the video. This tool was initially designed assuming videos use inter-frame codecs (like H.264/H.265) where I-frames are sparse.

If you wanted to extract relevant frames from your video, it shouldn't be very hard by using either get_keyframes_color or get_keyframes_flow and a fake iframes list with fixed intervals. That is, you would extract all frames and then send only 1 frame every 48, for example, to either of these two functions. Note that for this approach you will have to extract every frame of the video which will take a substantial amount of disk space.

Something like this should work without having to modify the source code:

import videokf as vf
from videokf.utils.vidutils import extract_frames, get_keyframes_color, get_keyframes_flow

video_file = "abc_fixed.mov"
ffmpeg_exe = "ffmpeg"   # or full path
ffprobe_exe = "ffprobe" # or full path

# Extract all frames first
frames_dir = extract_frames(ffmpeg_exe, video_file)

# Create fake "iframes" at fixed intervals (e.g., every 24 frames = 1 second)
total_frames = 19758
interval = 24
fake_iframes = list(range(0, total_frames, interval))
# Make sure the last frame is included as an endpoint
if fake_iframes[-1] != total_frames:
    fake_iframes.append(total_frames)

# Now run the analysis - it will pick 1 keyframe per 24-frame window
keyframes = get_keyframes_color(fake_iframes, frames_dir)
# or
# keyframes = get_keyframes_flow(fake_iframes, frames_dir)

print(f"Got {len(keyframes)} keyframes")  # ~823 keyframes

However, this is not efficient at all and the best solution would be to modify the source code to use ffmpeg to extract only the relevant frames and analyze only those. Maybe using something like this:

# Extract 1 frame per second (at 24fps, every 24th frame)
ffmpeg -i "abc_fixed.mov" -vf "select='not(mod(n,24))'" -vsync vfr "keyframes_3/frame_%04d.jpg"