[SoX-devel] [ sox-Bugs-2864539 ] WAV 2 uLAW conversion fails occassionally

[SourceForge.net <no...@so...>]

Bugs item #2864539, was opened at 2009-09-22 15:49
Message generated for change (Comment added) made by ontheedge
You can respond by visiting: 
https://sourceforge.net/tracker/?func=detail&atid=110706&aid=2864539&group_id=10706

Please note that this message will contain a full copy of the comment thread,
including the initial issue submission, for this request,
not just the latest update.
Category: None
Group: unverified
Status: Open
Resolution: None
Priority: 5
Private: No
Submitted By: OnTheEdge (ontheedge)
Assigned to: Nobody/Anonymous (nobody)
Summary: WAV 2 uLAW conversion fails occassionally

Initial Comment:
We create WAV files from a TTS engine (NeoSpeech) on a Windows 2k3 server and execute Sox 14.3 (and 12.17.x) to convert them to headless-uLAW files.  99% of the time the conversion works just fine and an 8-bit 8KHz PCM wav file is converted to an 8-bit 8KHz mono headerless uLAW file. 

However once in a while the SoX generates a 16-bit 48KHz PCM file despite the command-line param that explicitly expects the output in uLAW.

If the initial errant 8-bit 8kHz PCM is converted, using SoX, to 16kHz and then converted back to a uLAW the resultant file is perfectly formed.
A careful review of the fields in the PCM data struct, and the WaveFormatEx header, of the errant WAV file, is identical to any other PCM file (except the 4-byte size field) that is sent to SoX as input and generates the well-formed output uLAW file.

If anyone can explain why this happens we would be really grateful.
Regards,
Edge.

----------------------------------------------------------------------

>Comment By: OnTheEdge (ontheedge)
Date: 2009-09-28 14:10

Message:
Sorry for the confusion, and thank you for taking an interest in my post.
I compared the PCM headers of both source PCM 8-bit 8kHz files.  They both
generate headerl-less uLAW files.  However most of the time I can drag the
output file (uLAW) into Goldwave and it asks about the format (which is
fine) and plays the file as an audio stream.
However occassionally the output file will have no obvious header
information ("RIFF' for example) but when dragged into Goldwave it is
recognized as a PCM 16-bit 48kHz format and just plays a squeaky sound.

Once a source file is identified as generating squeaky output I can
continually execute SoX using the cmd-line params shown here to reproduce
the problem:

> SoX  -t wav SourceFile.WAV   -t ul -r 8000 OutputFile.WAV.WAV

Converting the 8kHz source file to a 16kHz PCM file and then converting it
to a uLAW file will work just fine.

If there's a way to upload 4 files (2 source files, and 2 output files one
of which is squeaky) I will be delighted to do so.
Regards,
Edge.


----------------------------------------------------------------------

Comment By: robs (robs)
Date: 2009-09-27 15:25

Message:
Please can you clarify: you mention examining the header of the errant
file, but prior to that you say that the target of the conversion is
header-less.
TIA.

----------------------------------------------------------------------

You can respond by visiting: 
https://sourceforge.net/tracker/?func=detail&atid=110706&aid=2864539&group_id=10706