[vdr] A backward compatible solution for the 2GB video file limit

[s.huelswitt@gmx.de (Stefan Huelswitt)]

Hi,

It is well known that VDR has a 2GB limit for it's video files.
This is due to the 32-bit signed integer used for the index
pointer. By now Klaus refuses any change in this area because
this would require to change the format of the index file and
wouldn't be backward compatible with the old format. I can
understand this very well and I'm not going to argument against
this.

But I think there is an (relatively) easy AND backward compatible
way to remove the 2GB limit:

Each index entry saved to the index file has this format:

struct tIndex { int offset; uchar type; uchar number; short reserved; };

"offset" is the file offset in question. As you can see, it's a
32-bit signed value. You can see a "reserved" field, too.

I suggest to change the VDR internal representation of the file
offset from int to unsigned long long (64-bit). For saving the
index entry I suggest this format:

struct tIndex { unsigned int offset; uchar type; uchar number;
                unsigned short offsetHi; };

where "offset" holds the lower 32-bit of the file offset and
"offsetHi" holds additional 16-bit. This change is backward
compatible because today the reserved word is zeroed out anyways
and for file sizes <2GB offsetHi would be zero too. So the index entry
for files <2GB is exactly the same in both represantations.
With the high offset the total range would be 48-bit means 256TB.

Let me know what you think?

PS: I'm not going to create any code unless there is a high
chance that this gets included...

Regards.

-- 
Stefan Huelswitt
huels@iname.com  | http://home.pages.de/~nathan


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