Correcting song length in ripped flac files

[markwoll]

Years ago I ripped most of my collection into flacs. Around a thousand cd's
I used cdex from several computers to my NAS.
It turned out that the song lengths for a bunch of albums is 3:22:00 ( 3 hours 22 min )
The other tags are correct but something about my wifi connection from one of the computers caused this to happen.
Later I replaced the wifi and the songs ripped to the correct time length. And cd ripped from a desktop with wired ethernet were fine.
I thought that I could fix it with Musicbrainz Picard by looking up the album and replacing the tags.
A week or so ago I started trying to fix up tags showing errors in Bliss.
Re - ripped some albums with dbPoweramp, that fixed it, but very time consuming. And also a great way to find cd's with unrecoverable errors ( surprise! )
Tried MP3tag and MusicBrainz Picard to replace the tags, but Picard does not replace the song length like I thought it had in the past.
Any suggestions on repairing the song length with a program?

[progmatist]

The song length error would exist in the file header, not necessarily the tag. You can use ffmpeg to correct this with the below script. Simply copy and paste the script into a text file, and change the file extension from .txt to .bat. Then copy and paste that batch file to every folder in question, and double click to execute. A new subfolder named "repaired" will be created in every folder in which it's copied and executed. That subfolder will contain the repaired flac files. The ID3 tags will be copied along with the files BTW.

script:

mkdir repaired
for %%a in ("*.flac") do c:\ffmpeg\ffmpeg -i "%%a" -c copy "repaired\%%~na.flac"

This assumes ffmpeg.exe is located in the folder also named ffmpeg on the c drive. If you place ffmpeg in some other folder, change c:\ffmpeg\ffmpeg to c:\some other folder\ffmpeg, replacing "some other folder" with whatever you name it.

[markwoll]

Cool, thanks.

[markwoll]

Hmmm, the batch ran, but didn't correct the song length

z:\media\Music\AJ. Croce\Transit>c:\users\mark\desktop\flacfix.bat

z:\media\Music\AJ. Croce\Transit>mkdir repaired

z:\media\Music\AJ. Croce\Transit>for %a in ("*.flac") do c:\Users\Mark\Downloads\bliss-analyser-windows-0.1.0\ffmpeg -i "%a" -c copy "repaired\%~na.flac"

z:\media\Music\AJ. Croce\Transit>c:\Users\Mark\Downloads\bliss-analyser-windows-0.1.0\ffmpeg -i "01-Maybe.flac" -c copy "repaired\01-Maybe.flac"
ffmpeg version 5.0-full_build-www.gyan.dev Copyright (c) 2000-2022 the FFmpeg developers
built with gcc 11.2.0 (Rev5, Built by MSYS2 project)
configuration: --enable-gpl --enable-version3 --enable-shared --disable-w32threads --disable-autodetect --enable-fontconfig --enable-iconv --enable-gnutls --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-sdl2 --enable-libdav1d --enable-libdavs2 --enable-libuavs3d --enable-libzvbi --enable-librav1e --enable-libsvtav1 --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxavs2 --enable-libxvid --enable-libaom --enable-libopenjpeg --enable-libvpx --enable-mediafoundation --enable-libass --enable-frei0r --enable-libfreetype --enable-libfribidi --enable-libvidstab --enable-libvmaf --enable-libzimg --enable-amf --enable-cuda-llvm --enable-cuvid --enable-ffnvcodec --enable-nvdec --enable-nvenc --enable-d3d11va --enable-dxva2 --enable-libmfx --enable-libshaderc --enable-vulkan --enable-libplacebo --enable-opencl --enable-libcdio --enable-libgme --enable-libmodplug --enable-libopenmpt --enable-libopencore-amrwb --enable-libmp3lame --enable-libshine --enable-libtheora --enable-libtwolame --enable-libvo-amrwbenc --enable-libilbc --enable-libgsm --enable-libopencore-amrnb --enable-libopus --enable-libspeex --enable-libvorbis --enable-ladspa --enable-libbs2b --enable-libflite --enable-libmysofa --enable-librubberband --enable-libsoxr --enable-chromaprint
libavutil 57. 17.100 / 57. 17.100
libavcodec 59. 18.100 / 59. 18.100
libavformat 59. 16.100 / 59. 16.100
libavdevice 59. 4.100 / 59. 4.100
libavfilter 8. 24.100 / 8. 24.100
libswscale 6. 4.100 / 6. 4.100
libswresample 4. 3.100 / 4. 3.100
libpostproc 56. 3.100 / 56. 3.100
Input #0, flac, from '01-Maybe.flac':
Metadata:
ARTIST : AJ. Croce
ALBUM : Transit
TITLE : Maybe
GENRE : Blues
DATE : 1999
track : 01
Duration: 03:22:53.94, start: 0.000000, bitrate: 20 kb/s
Stream #0:0: Audio: flac, 44100 Hz, stereo, s16
Stream #0:1: Video: mjpeg (Baseline), yuvj420p(pc, bt470bg/unknown/unknown), 300x300 [SAR 1:1 DAR 1:1], 90k tbr, 90k tbn (attached pic)
Metadata:
comment : Cover (front)
Output #0, flac, to 'repaired\01-Maybe.flac':
Metadata:
ARTIST : AJ. Croce
ALBUM : Transit
TITLE : Maybe
GENRE : Blues
DATE : 1999
track : 01
encoder : Lavf59.16.100
Stream #0:0: Video: mjpeg (Baseline), yuvj420p(pc, bt470bg/unknown/unknown), 300x300 [SAR 1:1 DAR 1:1], q=2-31, 90k tbr, 90k tbn (attached pic)
Metadata:
comment : Cover (front)
Stream #0:1: Audio: flac, 44100 Hz, stereo, s16
Stream mapping:
Stream #0:1 -> #0:0 (copy)
Stream #0:0 -> #0:1 (copy)
Press [q] to stop, [?] for help
frame= 1 fps=0.0 q=-1.0 Lsize= 30383kB time=00:03:58.14 bitrate=1045.1kbits/s speed= 430x
video:21kB audio:30353kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 0.027110%

[markwoll]

Running this command worked to correct the song length and put it in the repaired folder
z:\media\Music\AJ. Croce\Transit>c:\Users\Mark\Downloads\bliss-analyser-windows-0.1.0\ffmpeg -i 01-Maybe.flac -f flac repaired\01-Maybef.flac
the -c might have something to do with it.

[markwoll]

removing the -c copy fixed it in the batch. Now it will copy to a 'repaired' folder with correct song lengths.
fixflac.bat

mkdir repaired
for %%a in ("*.flac") do c:\Users\Mark\Downloads\bliss-analyser-windows-0.1.0\ffmpeg -i "%%a" -f flac "repaired\%%~na.flac"

[progmatist]

^^ Come to think of it, the -c copy tells ffmpeg to copy without modification. Which would of course also copy over the song length error.