[vorbis-dev] frame_info_add

[macik.sk at post.sk]

 Hi,

I have this idea:

It can be useful to have for each frame two variables stored in bitstream that will hold information about starting and ending position of \"valid\" samples in the frame.

With these additional information it will be possible to do simple editing (like cutting or concatenating two streams) without decompressing/recompressing at sample-granularity.

Simple example (size of frame==10 samples):

| frame1  | frame2  | frame3  | frame4
|         |         |         |
0000000000111111111122222222223333333333 : sample count
0123456789012345678901234567890123456789 : sample count
|         |         |         | 
A 0,9     B 0,9     C 0,9     D 0,9      

A,B,C,D : compressed frames
numbers 0,9: start and end position of valid pcm samples (new variables I\'m talking about).

for example we need to cut samples 15 to 32. New bitstream can look like:

A 0,9 B 0,5 D 2,9 
or
A 0,9 B 0,5 C 0,-1 D 2,9
Decoder decodes whole frame but should be able to write out only valid data == 22 samples.

I know it may cause inner fragmentation but advantages are promising (audio HD recording, video post production - all without recompressing)...

PS:Maybe I\'m missing something, I looked at sources only yeasty.
PS2: All of this can be applied at application-side too so it is only proposition.

macik

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