[XviD-devel] padding bytes in stream?

Stephan Assmus superstippi at gmx.de
Tue Jul 3 09:22:53 CEST 2007


Hello all,

First of all, thank you for a great software package! It is clean and well 
documented, it was easy to dive into it and be productive quickly. Thanks!

I was wondering about the decode example with regards to MIN_USEFUL_BYTES 
(defined to 1). In the example, new data is fetched when there is less or 
equal to MIN_USEFUL_BYTES left in the source buffer. I used this code to 
write a BeOS decoder plugin. There is a function that the decoder can use, 
which will give it the "next chunk" of data from the extractor (ie AVI). I 
keep fetching chunk buffers and feeding them into xvid until I successfully 
decoded a frame. On the next request to decode a frame, I feed the left 
over bytes of the last chunk buffer into xvid and start fetching the next 
chunks and so on. My question is about MIN_USEFUL_BYTES. When xvid left 
just 1 byte in the buffer, should I prepend that byte to the next buffer or 
can it be safely discarded (like it is just some kind of padding). Right 
now, I just discard this byte and the codec seems to work fine, but someone 
looked over my code and spotted this and said I should probably not drop 
that byte... any insights?

Thanks and best regards,
-Stephan


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