11 Feb
2004
11 Feb
'04
4:14 a.m.
Hi peeps,
I've only just started playing with libsndfile, so I hope this
isn't a dumb question.
I get a segmentation fault when I try to use sf_readf_float on some
wavs. The odd thing is, if I re-save the file in the same format,
(with something like audacity or sweep) it works. I thought I must
have been confused, and that the format was different the next time
around, but it isn't - at least as far as libsndfile's SF_INFO can
tell me.
I don't think the file is broken, because audacity, sweep, mplayer,
etc. can all load and play it without any complaint.
And it's not just one file - it's quite a few of them.
What am I doing wrong?
I've packed up an example (small - just a kick) in working and
broken form in case anyone wants to try it. It's at
http://www.dis-dot-dat.net/busted.tar.bz2
Thanks for listening.
James
11 Feb
11 Feb
5:19 a.m.
On Wed, 11 Feb 2004 09:08:58 +0000
james(a)dis-dot-dat.net wrote:
Hi peeps,
I've only just started playing with libsndfile, so I hope this
isn't a dumb question.
What version of libsndfile?
I get a segmentation fault when I try to use
sf_readf_float on some
wavs.
Are you sure the array you are reading into is large enough? Both the
files in tha tar.bz2 file were stereo. When you read a stereo file with
sf_readf_float, and ask for N frames, the destination array must be
2 * N in size.
The odd thing is, if I re-save the file in the same
format,
(with something like audacity or sweep) it works.
Audacity and Sweep both use libsndfile for file I/O.
I thought I must
have been confused, and that the format was different the next time
around, but it isn't - at least as far as libsndfile's SF_INFO can
tell me.
I don't think the file is broken,
Correct, the files are fine.
Erik
--
+-----------------------------------------------------------+
Erik de Castro Lopo nospam(a)mega-nerd.com (Yes it's valid)
+-----------------------------------------------------------+
"Linux everywhere pretty much eliminates the need for Java everywhere"
-- Bruce Ide in letter to LWN editors
6:05 a.m.
On Wed, 11 Feb, 2004 at 09:14PM +1100, Erik de Castro Lopo spake thus:
Yes, the buffer is info->frames*info->channels big.
It's exactly the same code in both cases - one file segfaults, the
other plays.
I kinda assumed they would - which just makes it all weirder.
And yet one kills libsndfile. Strange.
On Wed, 11 Feb 2004 09:08:58 +0000
james(a)dis-dot-dat.net wrote:
1.0.5
Hi peeps,
I've only just started playing with libsndfile, so I hope this
isn't a dumb question.
What version of libsndfile? I get a
segmentation fault when I try to use sf_readf_float on some
wavs.
Are you sure the array you are reading into is large enough? Both the
files in tha tar.bz2 file were stereo. When you read a stereo file with
sf_readf_float, and ask for N frames, the destination array must be
2 * N in size. The odd thing
is, if I re-save the file in the same format,
(with something like audacity or sweep) it works.
Audacity and Sweep both use libsndfile for file I/O. I thought I
must
have been confused, and that the format was different the next time
around, but it isn't - at least as far as libsndfile's SF_INFO can
tell me.
I don't think the file is broken,
Correct, the files are fine. Erik
3:51 p.m.
On Wed, 11 Feb 2004 11:00:34 +0000
james(a)dis-dot-dat.net wrote:
On Wed, 11 Feb, 2004 at 09:14PM +1100, Erik de Castro
Lopo spake thus:
Please try 1.0.6 which has just been released.
If it still crashes with 1.0.6, please send me the smallest possible code
example that reproduces the problem.
Erik
--
+-----------------------------------------------------------+
Erik de Castro Lopo nospam(a)mega-nerd.com (Yes it's valid)
+-----------------------------------------------------------+
"These are the finest moments in (post)modern life, when satire is completly
indistinguishable from reality... I usually have to rely on the presidential
elections for such dada." -- frenomulax on Jesux a christian Linux distro.
On Wed, 11 Feb 2004 09:08:58 +0000
james(a)dis-dot-dat.net wrote:
1.0.5 Hi peeps,
I've only just started playing with libsndfile, so I hope this
isn't a dumb question.
What version of libsndfile?
4:37 p.m.
On Thu, 12 Feb, 2004 at 07:47AM +1100, Erik de Castro Lopo spake thus:
On Wed, 11 Feb 2004 11:00:34 +0000
james(a)dis-dot-dat.net wrote:
Well, I've stopped the crashing.
It was my bad, but still a bit confusing.
Here's what I was doing
samples=info->frames*info->channels;
sound=(sample_t *) malloc (samples * sizeof(sample_t));
sf_readf_float(f,sound,samples);
Which (I now realise) isn't quite right because I'm trying to read
twice as many frames as there are in the file (assuming a stereo
file).
Changing to sf_read_float does the trick, but I still don't understand
why some stereo files worked, while others didn't. Opening them in
something wlse and saving them again in exactly the same format made
them work!
Also, shouldn't sf_readf_float handle being asked to read too many
frames?
James
On Wed, 11 Feb, 2004 at 09:14PM +1100, Erik de
Castro Lopo spake thus:
Please try 1.0.6 which has just been released.
If it still crashes with 1.0.6, please send me the smallest possible code
example that reproduces the problem. On Wed, 11 Feb 2004 09:08:58 +0000
james(a)dis-dot-dat.net wrote:
1.0.5 Hi peeps,
I've only just started playing with libsndfile, so I hope this
isn't a dumb question.
What version of libsndfile? Erik
12 Feb
12 Feb
5:04 a.m.
On Wed, 11 Feb 2004 21:32:03 +0000
james(a)dis-dot-dat.net wrote:
Well, I've stopped the crashing.
It was my bad, but still a bit confusing.
Here's what I was doing
samples=info->frames*info->channels;
sound=(sample_t *) malloc (samples * sizeof(sample_t));
sf_readf_float(f,sound,samples);
Which (I now realise) isn't quite right because I'm trying to read
twice as many frames as there are in the file (assuming a stereo
file).
The cause of this is rather subtle. If you use the sndfile-info
program in the file x_kick.wav that you posted, you will notice
that there is non-audio data following the audio data. The
problem is that using sf_readf_float() is attempting to read this
data as audio data.
Changing to sf_read_float does the trick, but I still
don't understand
why some stereo files worked, while others didn't.
The problem free files did not have the trailing non-audio data.
Opening them in
something wlse and saving them again in exactly the same format made
them work!
Saving the file probably removed that trailing non-audio data. Use
the sndfile-info program to verify this.
Also, shouldn't sf_readf_float handle being asked
to read too many
frames?
Yes, thats a bug. Fix in progress.
Erik
--
+-----------------------------------------------------------+
Erik de Castro Lopo nospam(a)mega-nerd.com (Yes it's valid)
+-----------------------------------------------------------+
Java : A language from the C family of languages. It has all the bad
features of C++ but without the most powerful feature of C, pointers.
--
+-----------------------------------------------------------+
Erik de Castro Lopo nospam(a)mega-nerd.com (Yes it's valid)
+-----------------------------------------------------------+
" ... new TV ad for Microsoft's Internet Explorer e-mail program which
uses the musical theme of the "Confutatis Maledictis" from Mozart's
Requiem. "Where do you want to go today?" is the cheery line on the
screen, while the chorus sings "Confutatis maledictis, flammis acribus
addictis,". This translates to "The damned and accursed are convicted
to the flames of hell."
2:41 p.m.
On Thu, 12 Feb, 2004 at 08:59PM +1100, Erik de Castro Lopo spake thus:
Thanks, that's great.
Heh! I didn't realise I was talking to the author.
Sorry if that last line sounded whiney and/or ungrateful - what I
should have said was : thanks so much for libsndfile.
James
On Wed, 11 Feb 2004 21:32:03 +0000
james(a)dis-dot-dat.net wrote:
Ahhh.
Well, I've stopped the crashing.
It was my bad, but still a bit confusing.
Here's what I was doing
samples=info->frames*info->channels;
sound=(sample_t *) malloc (samples * sizeof(sample_t));
sf_readf_float(f,sound,samples);
Which (I now realise) isn't quite right because I'm trying to read
twice as many frames as there are in the file (assuming a stereo
file).
The cause of this is rather subtle. If you use the sndfile-info
program in the file x_kick.wav that you posted, you will notice
that there is non-audio data following the audio data. The
problem is that using sf_readf_float() is attempting to read this
data as audio data. Changing to
sf_read_float does the trick, but I still don't understand
why some stereo files worked, while others didn't.
The problem free files did not have the trailing non-audio data.
Opening them in
something wlse and saving them again in exactly the same format made
them work!
Saving the file probably removed that trailing non-audio data. Use
the sndfile-info program to verify this. Also,
shouldn't sf_readf_float handle being asked to read too many
frames?
Yes, thats a bug. Fix in progress. Erik
3:02 p.m.
On Thu, 12 Feb 2004 19:36:19 +0000
james(a)dis-dot-dat.net wrote:
Heh! I didn't realise I was talking to the
author.
Thats the internet. Sometimes you're talking to some 12 year old and
sometimes you're not :-).
Sorry if that last line sounded whiney and/or
ungrateful -
It didn't and I get even more annoyed with bugs in libsndfile than
you do.
Cheers,
Erik
--
+-----------------------------------------------------------+
Erik de Castro Lopo nospam(a)mega-nerd.com (Yes it's valid)
+-----------------------------------------------------------+
"The earth is degenerating these days. Bribery and corruption abound.
Children no longer mind parents ...and it is evident that the end of
the world is approaching fast." -- Assyrian Tablet Engraved in 2800 B.C.
--
+-----------------------------------------------------------+
Erik de Castro Lopo nospam(a)mega-nerd.com (Yes it's valid)
+-----------------------------------------------------------+
"The RIAA is obsessed to the point of comedy with the frustration
of having its rules broken, without considering whether such rules
might be standing in the way of increased revenues. Indeed,
Napster and Gnutella may turn out to be the two best music-marketing
gimmicks yet devised, if only the RIAA would take its head out of
its ass long enough to realise it."
-- Thomas C Greene on www.theregister.co.uk
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