21 Jan
2006
21 Jan
'06
8:45 a.m.
Hi all,
is there a recommended way to write / read additional chunks in
WAV files, using libsndfile (assuming it's possible at all - I
didn't find any hints to this in the docs) ?
What I need in particular is some way to calibrate the time
axis - i.e. to say frame #N corresponds to t = 0, and some
other similar info, mostly sample indices.
TIA,
--
FA
21 Jan
21 Jan
4:31 p.m.
Am Samstag, 21. Januar 2006 14:51 schrieb fons adriaensen:
Hi all,
is there a recommended way to write / read additional chunks in
WAV files, using libsndfile (assuming it's possible at all - I
didn't find any hints to this in the docs) ?
Not sure if this is possible with libsndfile. If not you could i.e. use the
RIFF classes of libgig:
http://cvs.linuxsampler.org/cgi-bin/viewcvs.cgi/libgig/src/RIFF.h
C++ though. :P
CU
Christian
23 Jan
23 Jan
5:02 p.m.
fons adriaensen wrote:
Hi all,
is there a recommended way to write / read additional chunks in
WAV files, using libsndfile (assuming it's possible at all - I
didn't find any hints to this in the docs) ?
libsndfile already supports the addition of a number of specific
chunk types like PEAK, strings in the INFO chunk etc.
What I need in particular is some way to calibrate the
time
axis - i.e. to say frame #N corresponds to t = 0, and some
other similar info, mostly sample indices.
There is no existing chunk type which does what you require. In
addition, it would be a bad idea to define your own custom
chunk type to do this.
However, it would be possible to add a comment string containing
the data you require as a text string. See:
http://www.mega-nerd.com/libsndfile/api.html#string
HTH,
Erik
--
+-----------------------------------------------------------+
Erik de Castro Lopo
+-----------------------------------------------------------+
"The object-oriented model makes it easy to build up programs by
accretion. What this often means, in practice, is that it provides
a structured way to write spaghetti code." -- Paul Graham
6:01 p.m.
On Tue, Jan 24, 2006 at 09:02:23AM +1100, Erik de Castro Lopo wrote:
fons adriaensen wrote:
Would it ? It solves the problem, and all other apps will - or
at least _should_ according to the WAV spec - just ignore it.
What problems would be created by adding a new chunk ?
The alternative would be a format that isn't standard at all.
What I need in particular is some way to
calibrate the time
axis - i.e. to say frame #N corresponds to t = 0, and some
other similar info, mostly sample indices.
There is no existing chunk type which does what you require. In
addition, it would be a bad idea to define your own custom
chunk type to do this. However, it would be possible to add a comment string
containing
the data you require as a text string. See:
http://www.mega-nerd.com/libsndfile/api.html#string
Yes, been there before I posted. It's probably a matter of taste,
but I don't find this much cleaner than adding a new chunk.
Thanks for the suggestions !
--
FA
6:18 p.m.
New subject: [linux-audio-dev] Additional chunks in WAV files with libsndfile ?
On Tue, 2006-01-24 at 00:08 +0100, fons adriaensen wrote:
On Tue, Jan 24, 2006 at 09:02:23AM +1100, Erik de
Castro Lopo wrote:
BWF supports such a timestamp (the origination time).
fons adriaensen wrote:
Would it ? It solves the problem, and all other apps will - or
at least _should_ according to the WAV spec - just ignore it.
What problems would be created by adding a new chunk ?
The alternative would be a format that isn't standard at all. What I need in particular is some way to
calibrate the time
axis - i.e. to say frame #N corresponds to t = 0, and some
other similar info, mostly sample indices.
There is no existing chunk type which does what you require. In
addition, it would be a bad idea to define your own custom
chunk type to do this. However, it
would be possible to add a comment string containing
the data you require as a text string. See:
http://www.mega-nerd.com/libsndfile/api.html#string
Yes, been there before I posted. It's probably a matter of taste,
but I don't find this much cleaner than adding a new chunk.
Thanks for the suggestions !
6:51 p.m.
fons adriaensen wrote:
Would it ? It solves the problem, and all other apps
will - or
at least _should_ according to the WAV spec - just ignore it.
What problems would be created by adding a new chunk ?
The alternative would be a format that isn't standard at all.
The problems are as follows:
- There are many very broken WAV (and AIFF) file parsers.
- There is no central registry of the chunk names and hence
your chunk name may colide with a current or future chunk
name defined by someone else.
Yes, been there before I posted. It's probably a matter of taste,
but I don't find this much cleaner than adding a new chunk.
It has the advantage of being robuts, future proof and usable
now.
Erik
--
+-----------------------------------------------------------+
Erik de Castro Lopo
+-----------------------------------------------------------+
C++: The power, elegance and simplicity of a hand grenade.
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linux-audio-dev@lists.linuxaudio.org
5 comments
4 participants
participants (4)
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Christian Schoenebeck -
Erik de Castro Lopo -
fons adriaensen -
Paul Davis