[Vorbis] ov_open_callbacks takes so much time to open 210 MB OGG file

Pavel Nikitenko pavnsw at gmail.com
Thu Dec 6 01:19:25 PST 2012


> What version of Vorbisfile are you using, and have you verified the
> Ogg file itself is correct?

The Ogg file is normally playable eg. in VLC media player.
It was created by similar code as it is encoder_example.cpp .
Only difference is that the file is not created at once via audio recording.
But step by step appended to it to the end of file. Every time the audio 
recording is stopped and then after some time started audio record 
again. Similar like concat command does.

I try debug version of the code in Visual Studio 2010 and if I break the 
code, it is in spending time in the

ov_open_callbacks(fd_, &vf, NULL, 0, OV_CALLBACKS_NOCLOSE)

function.

If I use OV_CALLBACKS_STREAMONLY_NOCLOSE instead, it does not take any 
time to open the 210 MB OGG file.

ov_open_callbacks(fd_, &vf, NULL, 0,OV_CALLBACKS_STREAMONLY_NOCLOSE)


If I use smaller OGG file like 2 MB OGG file, it does not take time to 
open the file even with OV_CALLBACKS_NOCLOSE .
I tested 50 MB OGG file, the code also opened it like instantly.
My system is Intel Core2 Duo CPU E6750 2.66GHz with 2 GB of RAM, Windows 
7 64 bit operating system.

Thanks and regards,
Pavel

On 6.12.2012 9:57, xiphmont at xiph.org wrote:
> On Wed, Dec 5, 2012 at 5:44 PM, Pavel Nikitenko <pavnsw at gmail.com> wrote:
>> Why ov_open_callbacks(fd_, &vf, NULL, 0, OV_CALLBACKS_NOCLOSE) takes so
>> long to open OGG file?
>> The OGG file has just 210 MB. It takes a lot of time open the file.
> What version of Vorbisfile are you using, and have you verified the
> Ogg file itself is correct?
>
> Is it the open process taking time, or is it the codec setup?  What
> profiling have you done?  What kind of system is this on?  X86,
> embedded...?
>
> Monty



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