CachingReader: Invalid sample position from engine

[mixxxbot]

Reported by: uklotzde
Date: 2017-02-19T19:06:31Z
Status: Fix Released
Importance: Critical
Launchpad Issue: lp1666050
Attachments: invalid_sample_read_request.txt

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Branch: master / 2.1

Deck 2 was playing and I was adjusting a cue point on deck 1. When hitting cue on deck 1 suddenly the music stopped. My first guess was a wrong midi mapping, but than I noticed that a debug assertion stopped Mixxx. Only a test run with controller debugging enabled ;)

Please see the attached stack trace.

[mixxxbot]

Commented by: uklotzde
Date: 2017-02-19T19:06:31Z
Attachments: invalid_sample_read_request.txt

[mixxxbot]

Commented by: uklotzde
Date: 2017-03-11T13:11:58Z

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This has now happened multiple times when setting a cue point. Only one deck is affected, it doesn't matter if another deck is playing or not. The engine code for calculating the sample offser when setting cue points is definitely broken!

[mixxxbot]

Commented by: daschuer
Date: 2017-03-13T10:01:39Z

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This is probably caused be the late latest changes, allowing fractional sample cue points.
We need to allow fractional hints for the caching reader as well.

[mixxxbot]

Commented by: uklotzde
Date: 2017-03-13T20:18:31Z

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I disagree. The caching reader can only read from frame boundaries. Sub-frame calculations must be done in the engine.

[mixxxbot]

Commented by: uklotzde
Date: 2017-03-13T20:21:05Z

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By switching to frame positions this would work as expected. It's just a missing adjustment of sample positions to even numbers during sub-frame calculations.

[mixxxbot]

Commented by: daschuer
Date: 2017-03-13T22:10:06Z

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Yes, the caching reader can only read full frames, and the engine can request fractional frames.
This bug is just an issue where we round to full frames. I have no strong opinion about the right place right now.

[mixxxbot]

Commented by: uklotzde
Date: 2017-03-14T06:24:47Z

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The sub-frame calculations (and interpolation) must be done once, but not twice. If resampling between the sampling rate provided by decoding and the internal rate of the engine is needed, that could be the right place.

[mixxxbot]

Commented by: Be-ing
Date: 2017-05-11T17:44:48Z

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#1223

[mixxxbot]

Issue closed with status Fix Released.