[Desktop-packages] [Bug 1654480]

2019-12-19 Thread Alex Korchemniy
Thanks. The patch is a significant improvement! At 4x with 10ms window, it's easy to comprehend speech. There is some slightly noticeable choppiness in some videos. I'm not an audio expert, but I tried to do some analysis using Audacity + Gimp. I plotted both track as Mel Spectrograms, took a scre

[Desktop-packages] [Bug 1654480]

2019-12-19 Thread Alex Korchemniy
>From the author: https://www.surina.net/article/time-and-pitch- scaling.html -- You received this bug notification because you are a member of Desktop Packages, which is subscribed to firefox in Ubuntu. https://bugs.launchpad.net/bugs/1654480 Title: HTML5 sound choppy when played at 4x Statu

[Desktop-packages] [Bug 1654480]

2019-12-19 Thread Alex Korchemniy
I started digging into the SoundTouch library and confirmed my suspicion. https://hg.mozilla.org/mozilla- central/file/tip/media/libsoundtouch/src/TDStretch.cpp#l637 Author says it's implemented using "WSOLA-like method". Waveform- similarity-based synchronized overlap-add. Maybe based on this pap

[Desktop-packages] [Bug 1654480]

2019-12-19 Thread Alex Korchemniy
Created attachment 9114054 2019-12-05_21-09-44 3x identical to 1x.png In this screenshot, the first track is Chrome, 2nd track is Firefox at 3x, and 3rd track is Firefox at 1x. -- You received this bug notification because you are a member of Desktop Packages, which is subscribed to firefox in U

[Desktop-packages] [Bug 1654480]

2019-12-19 Thread Alex Korchemniy
Created attachment 9114055 2019-12-05_21-14-30 missing samples.png Top is 3x. Bottom is 1x. Estimate of the amount of audio data that is skipped before waveforms align. -- You received this bug notification because you are a member of Desktop Packages, which is subscribed to firefox in Ubuntu. h

[Desktop-packages] [Bug 1654480]

2019-12-19 Thread Alex Korchemniy
I used MOZ_DUMP_AUDIO=1 to capture samples from 1x vs 3x. The waveforms at 3x are identical to 1x for about 45ms. Then it skips and copies another 45ms. -- You received this bug notification because you are a member of Desktop Packages, which is subscribed to firefox in Ubuntu. https://bugs.launc

[Desktop-packages] [Bug 1654480]

2019-12-19 Thread Alex Korchemniy
With the SoundTouch algorithm there isn't much improvement with a window size below 10ms. I found a quicker way to test various parameters using mpv, which uses same/similar algo. When I get some time I'll generate random samples with various parameters and do a blind perceptual test. mpv --af=sca

[Desktop-packages] [Bug 1654480] Re: HTML5 sound choppy when played at 4x

2018-07-15 Thread Alex Korchemniy
This bug should have been opened with Firefox instead. I found the ticket: https://bugzilla.mozilla.org/show_bug.cgi?id=1427267 ** Bug watch added: Mozilla Bugzilla #1427267 https://bugzilla.mozilla.org/show_bug.cgi?id=1427267 -- You received this bug notification because you are a member of

[Desktop-packages] [Bug 1654480] [NEW] HTML5 sound choppy when played at 4x

2017-01-05 Thread Alex Korchemniy
Public bug reported: I use a bookmarklet to set the playback rate on the HTML5 player element to 4x (tested with YouTube). Chrome handles the audio flawlessly, but Firefox becomes choppy after 2x. Here's the bookmarklet. The following line may get mangled or removed... "javascript:%7Bvar%20v%3Ddo