<Sound Dev> [9] Review Request: 8152501 closed/javax/sound/sampled/FileWriter/WaveBigEndian.java failing

[Alex Menkov]

Why you don't want to fix 24 & 32+ bits right now?
Idea to have "partially fixed" does not look good to me (BTW maybe the 
test should be extended to verify 24bit conversions too?)

--alex

On 29.03.2016 14:33, Sergey Bylokhov wrote:
> Hello,
> Please review the fix for jdk9.
>
> Description:
>   After the jigsaw integration the closed test WaveBigEndian fails. The
> reason is that the order of service providers is not specified in the
> jigsaw(I guess it will be changed in the future).
> The test verify that the audio data(pcm signed) during conversion is not
> changed corrupted. The java sound has two codecs which can convert pcm
> signed: PCMtoPCMCodec(base on int) and AudioFloatConverter(based on
> float). It was found that the test fails when AudioFloatConverter is
> used. This is because PCMtoPCMCodec converts data of
> pcm_signed/pcm_unsigned directly, and AudioFloatConverter converts data
> to the intermediate floats[-1.0; 1.0] and then converts it to the target
> format.
>
> Example of formulas are used by AudioFloatConverter.
>   - Signed byte to/from float: byte / 127.0f <--> byte * 127. Has a
> problem with a minimum byte "-128". it is outside of "(float) -1"
>   - Signed byte to/from unsigned: byte + 127 <--> byte - 127. Converts
> "-128" to "-1" instead of zero, and 127 to "254" instead of 255.
>
> Similar issues exists for 16 bits/32bits.
> The code was change to:
>   - Signed byte to/from float: byte > 0 ? byte / 127.0f : byte / 128.0f
>   - Signed byte to/from unsigned: byte + 128 <--> byte - 128.
>
> Note that for 32 bits only the second step is changed,
> division/multiplication error is quite tiny in this case.
>
> Also note that PCMtoPCMCodec can be removed after this fix, I'll do that
> later if the performance of two codecs is similar. I guess other
> conversions(LSB, 24 bit, 32+) in AudioFloatConverter should be
> investigated also, I'll do that later.
>
> Bug: https://bugs.openjdk.java.net/browse/JDK-8152501
> Webrev can be found at: http://cr.openjdk.java.net/~serb/8152501/webrev.00
>