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IDProjectCategoryView StatusLast Update
0001438OpenMPTAudio I/Opublic2021-10-16 12:23
Reportersqrmax Assigned Tomanx  
PrioritynormalSeverityminorReproducibilityunable to reproduce
Status feedbackResolutionopen 
Platformx86OSWindowsOS VersionXP
Product VersionOpenMPT 1.28.09.00 / libopenmpt 0.4.11 (upgrade first) 
Target VersionOpenMPT 1.30.01.00 / libopenmpt 0.6 (upcoming stable) 
Summary0001438: Opus streaming export --- unexpected volume ramp
Description

When exporting to Opus, the beginning of the resulting file has a short volume ramping period for a fraction of a second. This mutes the first attack in songs. Such ramping is not present in wav or ogg exports.

Steps To Reproduce

Load a module, and stream using the File menu. Set Opus output, Q5, 48khz, stereo, play the entire song, normalize output. Examine the beginning of the file, and compare this to the wav and ogg outputs.

The volume ramping with Opus seems to occur regardless of the module.

TagsNo tags attached.
Has the bug occurred in previous versions?
Tested code revision (in case you know it)

Activities

manx

manx

2021-10-16 12:23

administrator   ~0004889

First off, Opus has no concept of quality, so the "Q5" you mentioned does not apply. I assumed VBR 128kbit for my testing, which is the default.
In any case, I cannot reproduce this problem with either 1.28 or 1.30. I cannot spot any additional ramping attenuation in exported opus files compared to wav.

Can you provide a short example file in both opus and wav format?

Which software are you using to look at the opus files? It may mishandle an OggOpus feature called pre-skip, which when mishandled could add additional samples prior to the intended data that ramp up in volume.

Also, did you change the hidden setting [Export]OpusComplexity (see <https://wiki.openmpt.org/Manual:_Hidden_Settings#.5BExport.5D>)? That might also introduce artifacts.

Issue History

Date Modified Username Field Change
2021-04-02 12:30 sqrmax New Issue
2021-04-03 15:33 manx Assigned To => manx
2021-04-03 15:33 manx Status new => assigned
2021-04-03 15:34 manx Status assigned => new
2021-10-15 09:06 manx Target Version => OpenMPT 1.30.01.00 / libopenmpt 0.6 (upcoming stable)
2021-10-16 12:23 manx Status new => feedback
2021-10-16 12:23 manx Note Added: 0004889
2021-10-16 12:23 manx Reproducibility always => unable to reproduce