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

[Sergey Bylokhov]

On 29.03.16 15:34, Alex Menkov wrote:
> 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?)

I am still not 100% sure that I understand correctly the code for 
non-integral types:
- LSB: when the number of bits is not dividable by 8
- 24 bits/32+ bits

My experiments show that there are possible issues related to 
overflow/underflow. So I postpones that change until I'll prove that the 
current code is ok and only the same change (like in this fix) is necessary.

> 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
>>


-- 
Best regards, Sergey.