Re: 32 Bit Float Problem

Am 17.01.2017 um 18:02 schrieb Måns Rullgård:
> Måns Rullgård <[email protected]> writes:
>
>> Thomas Foerster <[email protected]> writes:
>>
>>> Hi,
>>>
>>> I am a little bit confused about the following procedure
>>> (Windows). What is wrong?
>>>
>>> 1. Take a usual 2ch/16 Bit/44,1 kHz WAV-File (CD)
>>> 2. To get a 32 Bit FLOAT 88200 Hz File:
>>> sox input_16_44100.wav" -b 32 -e float output_88200_32F.wav rate -s -a
>>> -v -L 88200
>>> 3. sox output_88200_32F.wav output_88200_32F.raw
>>>
>>> The *.raw file has 58 bytes less-> the Wav-Float-Header has a size of
>>> 58 bytes. My own codecannot read this header in Audio format 3 (only
>>> wav-PCM and Extensible like 24 Bit Wav and 32 Bit Wav). I looked
>>> inside with Hex-Editor:
>>>
>>> -4 byte fact-chunk is beginning at byte 38
>>> -4 byte data-chunk is beginning at byte 50 ("usually" before fact-chunk)
>>>
>>> I could not read the size of the raw-data-chunk (raw data
>>> length). Theses bytes are at the end of the header. Here(hex): 00 00
>>> D8 0E ->
>>> 55310 bytes, what is wrong!
>>> It should be (dec:) 249036800bytes! This would be 0E D8 00 00 -> most
>>> significant bit!
>>>
>>> Then I tried this:
>>> sox.exe -r 88200 -e float -b 24 -c 2output_88200_32F.raw out.wav
>>> Error!
>>> This would be working (but makes no sense...):
>>> sox.exe -r 88200 -e signed-integer -b 24 -c 2output_88200_32F.raw out.wav
>>>
>>> Any idea?
>> Can you post a hex dump of the full header?
> The dump you sent (and please stay on the mailing list) looks fine.
>
> The data chunk size has the bytes 0x00 0x00 0xd8 0x0e, which read as
> *little endian* is 0xed80000 or 249036800 in decimal, just like you said
> it should be.
>
> All values in wav files are stored as little endian.
>

There is something wrong in my own new code (struct) for this format. I 
wasn't familiar with these ULAW, ALAW formats. My sox-command was also 
wrong. Should be:

sox -r 88200 -b 32 -c 2 -e float output_88200_32F.raw out.wav

Thank you Måns!

Regards
Thomas

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