MP3 output is audible, but test not pass
Hi everyone. I made small changes in
membrane_mp3_lame_plugin to support other input config (the original repo only support 44100/32/1).
(patch branch: https://github.com/yujonglee/membrane_mp3_lame_plugin/commits/patch/)
After the change, I run the test, but test does not pass.
But when I play the generated output file, it is audible and feels same as ref.mp3.
(To get generated audio, I commented out https://github.com/yujonglee/membrane_mp3_lame_plugin/blob/patch/test/integration/integration_test.exs#L27 and run test)
I wrote a README on how I create new test audio file:
https://github.com/yujonglee/membrane_mp3_lame_plugin/blob/patch/README.md
Can anyone share some insight on this?4 Replies
👋 that’s because this plugin uses snapshot testing. We check if the mp3 is exactly the same as the fixture that we confirmed to be audible and playable by popular players. That prevents introducing unintentional changes to the output mp3. However, if you change the encoder parameters, it’s necessary to manually verify that the output is correct and update the fixture 😉
@mat_hek Thank you!
Actually, I regenerated the fixture with
ffmpeg command, and ran the tests.
https://github.com/yujonglee/membrane_mp3_lame_plugin/blob/patch/README.md#test-file-generation
So output of my ffmpeg command is now new ref.mp3 . Both <generated_from_pipeline>.mp3 and ref.mp3 is audible, but they don't match.GitHub
membrane_mp3_lame_plugin/README.md at patch · yujonglee/membrane_mp...
Membrane MP3 encoder based on Lame. Contribute to yujonglee/membrane_mp3_lame_plugin development by creating an account on GitHub.
It's unlikely that the mp3 generated with FFmpeg will be exactly the same as generated by Membrane. You should generate the output with Membrane, check if it's correct and then use it as the reference 😉
Didn't know that they are not same 🙂 Thank you