Subject: Re: [linux-audio-dev] libsndfile breakage
From: james_AT_dis-dot-dat.net
Date: Thu Feb 12 2004 - 21:36:19 EET
On Thu, 12 Feb, 2004 at 08:59PM +1100, Erik de Castro Lopo spake thus:
> On Wed, 11 Feb 2004 21:32:03 +0000
> james_AT_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.
Ahhh.
> > 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.
Thanks, that's great.
> > Also, shouldn't sf_readf_float handle being asked to read too many
> > frames?
>
> Yes, thats a bug. Fix in progress.
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
> Erik
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