lp1766834: Detect M4A decoding errors on Windows

[uklotzde]

https://bugs.launchpad.net/mixxx/+bug/1766834

I don't know how frequently the decoder gets out of sync while reading. Currently we have only a single
example provided by Sean. But it is definitely a critical issue if playback or analysis stops unexpectedly!!

[uklotzde]

Still doesn't work as expected, need more testing. Rounding errors seem to accumulate while reading. i.e. the reader is reporting inaccurate positions.

[uklotzde]

Finally I understood that the example file is actually corrupt and IMFSourceReader is reporting wrong read positions! The implementation is now more robust and logs those errors, many errors.

I'm won't touch this again without any important reasons to do so. Lots of wasted time hunting ghost bugs, frustrating. ClosedFinished.

[Pegasus-RPG]

I'm confused. What does this PR end up doing? More error-checking such that corrupt files are handled more gracefully?

[uklotzde]

• Even the previous rounding code should have worked for regular files. Now the conversions are easier to grasp.
• The reading code is more robust if wrong stream positions are reported and ignores them if possible.

In the end this might not even be a bug in our code, although improving robustness for corrupt files is at least one actual benefit. Otherwise the effort I spent on this would be totally lost.

[uklotzde]

Reading should not abort without an indication why. Now you get some nice logs:

SoundSourceMediaFoundation - streamPos [100 ns] = 1625170 , sampleRate [Hz] = 44100
SoundSourceMediaFoundation - Stream position (in sample frames) while reading is inaccurate: expected = 7168 actual = 7167
SoundSourceMediaFoundation - streamPos [100 ns] = 1857369 , sampleRate [Hz] = 44100
SoundSourceMediaFoundation - Stream position (in sample frames) while reading is inaccurate: expected = 8192 actual = 8191
SoundSourceMediaFoundation - streamPos [100 ns] = 2089569 , sampleRate [Hz] = 44100
SoundSourceMediaFoundation - Stream position (in sample frames) while reading is inaccurate: expected = 9216 actual = 9215
SoundSourceMediaFoundation - streamPos [100 ns] = 2321768 , sampleRate [Hz] = 44100
SoundSourceMediaFoundation - Stream position (in sample frames) while reading is inaccurate: expected = 10240 actual = 10239
SoundSourceMediaFoundation - streamPos [100 ns] = 2553968 , sampleRate [Hz] = 44100
SoundSourceMediaFoundation - Stream position (in sample frames) while reading is inaccurate: expected = 11264 actual = 11263
SoundSourceMediaFoundation - streamPos [100 ns] = 2786167 , sampleRate [Hz] = 44100
SoundSourceMediaFoundation - Stream position (in sample frames) while reading is inaccurate: expected = 12288 actual = 12287
SoundSourceMediaFoundation - streamPos [100 ns] = 3018367 , sampleRate [Hz] = 44100
SoundSourceMediaFoundation - Stream position (in sample frames) while reading is inaccurate: expected = 13312 actual = 13311
SoundSourceMediaFoundation - streamPos [100 ns] = 3250566 , sampleRate [Hz] = 44100
SoundSourceMediaFoundation - Stream position (in sample frames) while reading is inaccurate: expected = 14336 actual = 14335
SoundSourceMediaFoundation - streamPos [100 ns] = 3482766 , sampleRate [Hz] = 44100
SoundSourceMediaFoundation - Stream position (in sample frames) while reading is inaccurate: expected = 15360 actual = 15359
SoundSourceMediaFoundation - streamPos [100 ns] = 3714965 , sampleRate [Hz] = 44100
SoundSourceMediaFoundation - Stream position (in sample frames) while reading is inaccurate: expected = 16384 actual = 16383
...
SoundSourceMediaFoundation - streamPos [100 ns] = 2528419047 , sampleRate [Hz] = 44100
SoundSourceMediaFoundation - Stream position (in sample frames) while reading is inaccurate: expected = 11150336 actual = 11150328
SoundSourceMediaFoundation - streamPos [100 ns] = 2528651247 , sampleRate [Hz] = 44100
SoundSourceMediaFoundation - Stream position (in sample frames) while reading is inaccurate: expected = 11151360 actual = 11151352
SoundSourceMediaFoundation - streamPos [100 ns] = 2528883446 , sampleRate [Hz] = 44100
SoundSourceMediaFoundation - Stream position (in sample frames) while reading is inaccurate: expected = 11152384 actual = 11152376
SoundSourceMediaFoundation - streamPos [100 ns] = 2529115646 , sampleRate [Hz] = 44100
SoundSourceMediaFoundation - Stream position (in sample frames) while reading is inaccurate: expected = 11153408 actual = 11153400
SoundSourceMediaFoundation - streamPos [100 ns] = 2529347845 , sampleRate [Hz] = 44100
SoundSourceMediaFoundation - Stream position (in sample frames) while reading is inaccurate: expected = 11154432 actual = 11154424
SoundSourceMediaFoundation - streamPos [100 ns] = 2529580045 , sampleRate [Hz] = 44100
SoundSourceMediaFoundation - Stream position (in sample frames) while reading is inaccurate: expected = 11155456 actual = 11155448

[uklotzde]

The deviations vary gradually, up to > 20 sample frames at some point.

[Pegasus-RPG]

Knowing why a problem is happening is much better in my view. I'm in favor of merging this.

[uklotzde]

Tested this with some valid M4A files. All reported stream positions are accurate, no log spam.

[daschuer]

LGTM. Thank you for nailing this down. Ready for merge.

[daschuer]

Ready for merge?

[daschuer]

@Pegasus-RPG merge?

[daschuer]

@Pegasus-RPG merge?

Since we get no answer I will merge it now. If there are still pending issues we can fix them later.