[ogg-dev] Using oggCat

[yorn at gmx.net]

Hey Brian,

I have had received a lot of complains about the concatenation of audio streams and I therefor decided to be very strict with the audio handling (the resulting file should always and ever be of good quality). That is the reason why sometimes the audio is reencoded even if it would fit.

Are you and your friend using the same version of oggCat (as it was handeled less strict in the version before)? Technically the code is completely the same on both systems. The only difference might be between 32 to 64 systems.

-yorn

BTW: you can also use oggSilence to produce a duration of silence. 



----- Ursprüngliche Nachricht -----
Von: Brian Rayne
Gesendet: 19.10.10 18:52 Uhr
An: ogg-dev at xiph.org
Betreff: [ogg-dev] Using oggCat

Hi, folks. I'm trying to prepend an OGG file with a given amount of silence. The solution that another developer and I are working with is to generate an audio file of a given duration of silence, convert that to OGG and use oggCat to try to append them.

This does work, however I'm seeing that in Windows, oggCat is seems to be re-encoding the audio (it counts from 0 to what I assume is the number of seconds of audio in the resulting file, taking a couple minutes, which is how long it would take to encode the audio in question). We've tried various things to ensure that the 2 OGG files are similar enough to be able to be concatenated without re-encoding, such as: Encoding a full song to OGG (in stereo, 192Kbps bit rate, 44.1KHz sample rate) using oggenc2 (a command line OGG encoder), creating a WAV file containing nothing but silence, reading the OGG's reported nominal bitrate (using the Vorbis API's vorbis_info structure) and encoding the WAV file to OGG (using the first OGG file's sample rate and nominal bit rate). Once both OGGs are created, when I use oggCat, it will still re-encode instead of doing a quick concatenation.

The other developer I'm working with says that when he does the same procedure in a *nix environment, it does not re-encode the audio. This is even though he is using the same methods that I am using in a Windows environment.

Can anybody determine if this is a bug? Or would somebody be willing to test oggCat by appending these two files together (file 1, then file 2) to see if oggCat is behaving different in Windows versus *nix, or if the files are somehow being created in some incompatible manner? The files in question are here:
http://www.sendspace.com/file/e3krsr 

Unless we can get oggCat to work as expected in our cross platform application, we won't be able to use it reliably. Thank you for any help you can provide.
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