This bug report was migrated from our old Bugzilla tracker.

These attachments are available in the static archive:

• A script to generate a testing files from one (it will generate various WAV files of various sample sizes and rates) (maketests.sh, application/x-sh, 2017-01-09 21:45:58 +0000, 407 bytes)
• Demo of bug (source and recorded result) (8bit-upsample-fail.7z, application/x-7z-compressed, 2017-01-09 21:48:01 +0000, 2642330 bytes)
• Experimental SDL_audiocvt.c whith my attempt to implement a fix (SDL_audiocvt.c, text/x-csrc, 2017-01-10 23:24:48 +0000, 34304 bytes)
• Fixed resampler (SDL_audiocvt.c.patch, text/plain, 2017-01-11 10:31:02 +0000, 1437 bytes)
• Fixed resampler (SDL_audiocvt.c.patch, text/plain, 2017-01-15 16:34:02 +0000, 1436 bytes)
• Fixed resampler (SDL_audiocvt.c.patch, text/plain, 2017-01-15 17:00:41 +0000, 1437 bytes)

Reported in version: HG 2.1
Reported for operating system, platform: All, All

Comments on the original bug report:

On 2017-01-09 21:45:58 +0000, Vitaly Novichkov wrote:

Created attachment 2670
A script to generate a testing files from one (it will generate various WAV files of various sample sizes and rates)

Just got review new changes in SDL Audio, and I though you are finally implemented right resampler and no more need to patch it, but a bug appears again...

Just my small gift for you - I made a small script which I used to quickly generate various WAV files (by using SoX utility) of various frequencies and bit sizes to test the resampling better. Use it (or any similar thing).

A Bug is same on both ways (up-sample and down-sample) and appears with 8-bit source samples. With 16-bit samples is fine (finally!).

Today I have no time to work, I hope you can fix this bug, or I'll try to fix it myself.

Some research:

• I tried to dump U8-to-F32, result seems fine.
• I tried to dump F32-to-U16, result is broken, but chain is going after SDL_ResampleAudioSimple function. Is very weird that this happen with 8-bit sound, mayby you forgot to update some length and in result a broken result?

On 2017-01-09 21:48:01 +0000, Vitaly Novichkov wrote:

Created attachment 2671
Demo of bug (source and recorded result)

This is my snapshot of buggy result. Source file (Unsigned 8-bit, 11025 hz Stereo), and resampled result (Signed 16-bit, 44100 hz Stereo)

On 2017-01-09 21:52:58 +0000, Vitaly Novichkov wrote:

EDIT: Bug is reproducing on ANY sound output, no matter bits. "Fine" result I got because in my player still be used my custom side resampler (which working for the 16-bit sound only) which now I disabled and just found that bug is no matter to source sample size.

On 2017-01-10 23:24:48 +0000, Vitaly Novichkov wrote:

Created attachment 2672
Experimental SDL_audiocvt.c whith my attempt to implement a fix

I have to implement a working resampler which is based on the old code of arbitrary resampler, but with the (rate_incr < 1.0) condition to choose to upsample or downsample, but I still need to fix an invalid code to have one "while" loop for both directions.

On 2017-01-11 10:31:02 +0000, Vitaly Novichkov wrote:

Created attachment 2674
Fixed resampler

I finally implemented the working two-direction resampler. Also, I made a small optimization and "consumed" variable is not needed.

On 2017-01-11 20:18:11 +0000, Vitaly Novichkov wrote:

P.S. Why you choose the "libsamplerate" instead of the "libsoxr"?
Audacity team are choose the libsoxr for their purposes: http://wiki.audacityteam.org/wiki/Libsoxr

On 2017-01-15 16:34:02 +0000, Vitaly Novichkov wrote:

Created attachment 2676
Fixed resampler

On 2017-01-15 16:38:21 +0000, Vitaly Novichkov wrote:

Just been updated patch to fit into recent change (adding two spaes)

On 2017-01-15 16:59:59 +0000, Vitaly Novichkov wrote:

Comment on attachment 2676
Fixed resampler

Ouch, typo (forgot to add some space, and result is rejecting patch)

On 2017-01-15 17:00:41 +0000, Vitaly Novichkov wrote:

Created attachment 2677
Fixed resampler

Now it's finally compatible with latest 938218064f67 revision

On 2017-01-17 19:27:07 +0000, Ryan C. Gordon wrote:

(In reply to Vitaly Novichkov from comment # 9)

Created attachment 2677 [details]
Fixed resampler

Now it's finally compatible with latest 938218064f67 revision

This patch looks reasonable; I'll try it today and hopefully apply it!

--ryan.

On 2017-01-18 07:13:39 +0000, Ryan C. Gordon wrote:

(In reply to Ryan C. Gordon from comment # 10)

(In reply to Vitaly Novichkov from comment # 9)

Created attachment 2677 [details]
Fixed resampler

Now it's finally compatible with latest 938218064f67 revision

This patch looks reasonable; I'll try it today and hopefully apply it!

--ryan.

Okay, your patch is now https://hg.libsdl.org/SDL/rev/efc103e60c5b

Thanks!

--ryan.