xiph / xiph/flac

Files that fail --keep-foreign-metadata

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Description

These are WAVE_FORMAT_PCM type files such that the apparent "WAVE_FORMAT_EXTENSIBLE"-type chunks should be ignored. flac.exe --keep-foreign-metadata alters them upon an encode-decode roundtrip.

https://www.hifistatement.info/downloads/14-09-01_peterson/Mellow_Tone_16-44.wav
https://www.hifistatement.info/downloads/14-09-01_peterson/Mellow_Tone_24-192.wav

Two discussions on whether they are compliant (and one more file): https://github.com/dbry/WavPack/issues/218 and https://hydrogenaudio.org/index.php/topic,128635

Addendum: some of the test files from that source behave this way, others don't. The person(s) who run the site might possibly know what software was used.

Contributor guide

Open the contributing guide

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Download the two linked WAV files and reproduce the flac.exe --keep-foreign-metadata encode-decode roundtrip. Start by tracing FLAC's handling of WAVE_FORMAT_PCM files with apparent WAVE_FORMAT_EXTENSIBLE chunks, using the linked discussions to understand the compliance question. Done means affected files retain their foreign metadata after the roundtrip, with regression coverage for the observed behavior.

Written by the indexing model from the issue text.

Assessment

Tech stack
c
Domain
audio-video-rtc
Issue type
Bug
Difficulty
4/5
Estimated time
3-5 days
Activity status
Quiet
Clarity
Mostly clear
Newbie friendliness
45/100

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