[vorbis-dev] Vorbis files merging

Vitaly Nechyos nvit at open.by
Thu Sep 19 10:16:02 PDT 2002



> At 03:05 PM 9/19/02 +0300, you wrote:
> >Good day.
> >
> >I have some questions dealing with merging Ogg Vorbis files.
> >Suppose I want merge two Ogg Vorbis files encoded with the same
parameters
> >into one file that composed of one logical bitstream. In this connection
> >some
> >questions:
> >A) Are codebooks in file headers depend only on Vorbis version and
> >    encoding parameters and don't depend on the particular source file?
>
> Yes (i.e. they aren't dependent on the input file)
>
> >B) Are the following steps enough to do merging?:
> >    - unset e_o_s flags in the last packet of the first file;
> >    - unset b_o_s flags in the first packet of the second file;
> >    - write additionally to the first file data data from the second
file,
> >which
> >      located after headers of the second file, at the same time changing
> >granuleposes
> >      and packetnos for packets from the second file;
>
> No. See vorbis-clip.txt in the documentation directory for some details,

It seems for me information in vorbis-clip.txt mostly concerns to extraction
a part
of a Vorbis file and saving it to another file, but not appending one file
to another.
Or i am wrong?

> and also consider the fact that vorbis packets are NOT independent
(because
> of overlap).
>
> Mike
>

vorbis-clip.txt says
"These segments are 'atomic' that is, one must recover the entire short time
segment
from the frame packet". It can be undestand as frame packets are
independent.
If they are not independent, how it can affects on appending operation?

One more question. Can one determine exact parameters  (i iterested in
quality value)
being used to encode a particular file? For example, i want to open a
file and make recording to the end of the file with encoding parameters of
the file.

Thanks.

Vitaly.

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