Re: [hatari-users] AVI Record problem -> ODML 64 bit support added

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Le 11/07/2017 à 15:50, Nicolas Pomarède a écrit :

I see AVI specs 2.0 can have extra AVIX chunks to have > 2GB in the end. I will try to look at this someday (but it might not be soon)


good news, Hatari now support the "OpenDML AVI File Format Extensions Specification" which extends the basic AVI format limited to 32 bit file size to handle file size of any size > 4GB.

I made some tests and successfully recorded a 7 GB file which I could read using VLC (including seeking anywhere using the indexes), some avi validation programs also reported a correct structure of the file.

For the technical details, the ODML format divides the AVI file in several RIFF AVI or RIFF AVIX (X=extension) chunks. Each chunks should be < 4GB but you can have as many as you like and some new "super indexes" are added to allow referencing position using 64 bit offset.

In Hatari, I arbitrarily fixed the super index size to 256 entries, each entries would then reference a 1 GB 'movi' chunk.

This requires an OS capable of handling 64 bit file offset, but all modern OSes will do it.

This means the current limit for an AVI file will now be 256 GB in Hatari :)


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