Re: [SoX-users] BWF support

[Jan S. <ha...@st...>]

Replying to myself,

On Sep 27 15:17:12, Jan Stary wrote:
> Since the very beginning, SoX supports the WAV file format.
> There doesn't seem to be any support for the BWF format,
> http://en.wikipedia.org/wiki/Broadcast_Wave_Format
> which is a kind of "augmented WAV", most notably supporting
> markers in the audio. A BWF file is just a WAV file with
> a richer header (more "chunks"); audio software that does
> not support BWF (such as sox) can simply treat it as a WAV
> (sox does, and plays them just fine).
> 
> Tons of audio software and hardware support WAV obviously,
> and support seems to be growing for the BWF. For example,
> my shiny new M-Audio Microtrack II recorder can record
> into BWF.
> 
> One nice application of having support of the markers in sox
> would be trimming by the markers. As in, say, a journalist
> records an interview into BWF, marking the beginning of each
> question. Then,
> 
> 	sox interview.wav question4.wav trim 4m 5m
> 
> Or, I make seven takes of a tuba solo, separated
> by the BWF markers; then,
> 
> 	sox solo.wav take5.wav trim 5m 6m
> 
> It would also play nicely with 'newfile' and 'restart' effects.

starting small, I wrote me a simple standalone tool
that parses some of the chunk types I have seen, and
just skips over others; here's the code:
http://stare.cz/~hans/.tmp/wavmeta.c

> Obviously, this needs thinking and code. Would please someone
> more knowledgeable point me to a place in the codebase where
> I could get started? Is there documentation of the internals?
> Is there a documented way to add a new format? Or does this
> simply go into src/wav.c?

Looking at the sox source, I am inclined to think that if I want to add
this metadata support into sox, I need to augment the display_file_info()
funtion, after adding certain fields to the sox_format_t structure,
right?

 	Thank you
 
 		Jan