[Matroska-devel] Re: WavPack hybrid

Steve Lhomme steve.lhomme at free.fr
Mon Dec 20 09:29:25 CET 2004


dbryant at impulse.net a écrit :
> Quoting Steve Lhomme <steve.lhomme at free.fr>:
> 
> 
>>Hi David,
>>
>>I can already mux basic WavPack files into Matroska. Now the 
>>interresting part is starting : hybrid mode. I almost have everything 
>>needed. Except that I don't know if I should keep the header of the 
>>correction part of if all data (except the CRC ?) are useless one you 
>>know it's a correction part.
> 
> 
> Yes, the only difference between the 32-byte headers of wv files and wvc
> files is the "crc" field. This is actually a little unfortunate because it
> would have been nice to have a flag bit to indicate the correction file. So
> now I have to look a little further into the data to make sure I have the
> right one, but it's not that big a deal.

Good. So maybe I'll only keep that. Maybe in the end a .wv+.wvc will be 
smaller in Matroska than the original files ;)

>>I want to keep as few useless data as possible. But still be allowed to 
>>extract data from Matroska and recover 100% of the original files.
>>
>>What do you think ?
>>
>>I already stip the header ID and packet size, and one is constant and 
>>the other is handled by Matroska.
> 
> 
> Sounds good. I also assume that you have the "index_no" and "track_no" taken
> care of in Matroska to handle complete CD images (although I do not use

Yes, but I wasn't sure about these ones. Are there already Wavpack files 
using multiple tracks ? The index is like a seek point ?

> these yet myself). I am now thinking of having a "IGNORE_BLOCK_INDEX" flag
> when opening WavPack streams so you won't have to worry about that. Of
> course, you will have to make sure that all of the blocks from the one
> marked "INITIAL_BLOCK" to the one marked "FINAL_BLOCK" are available to the
> decoder when you have more than 2 channels (or if someone encodes 2 channels
> with 2 mono streams).

Mh, I don't really understand. Why ? Can't you cut a Wavpack file 
wherever you want ?



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