[theora] mixing effects when joining videos

[Gregory Maxwell]

On Thu, Jun 18, 2009 at 10:52 AM, Ondrej Certik<ondrej at certik.cz> wrote:
>> The recommended technique is to initially encode to lossless (if
>> possible; usually for shorter material) or near lossless (i.e iframe
>> dirac at zillion mbit/sec) and only do low quality transcodes at the
>> final rate when everything is done.
>>
>> Failing that you don't have many other options. You can try to do some
>> fancy stream splicing so that the unmixxed parts take no loss.
>
> Ah I see, thanks. Btw, something like flac for video would be handy
> here. I am saving my screencast to png images and it's very big. For
> this particular purpose, I think just taking the difference of
> successive frames and encoding that as png would save lots of space,
> I'll try it.

Ogg/Dirac in lossless mode, although the cpu complexity is may be more
than you would like.

MNG is probably the best pre-existing fit for this simple application.
Too bad no one implements it! :)

>> Last I checked you couldn't upload Ogg/Theora to Youtube. I have no
>> clue how they would handle variable frame rate streams.
>
> Actually it works perfectly now. Here are two git video tutorials that
> I made yesterday and I encoded to theora from png images and then
> uploaded to youtube:
>
> http://code.google.com/p/sympy/wiki/GitTutorials

Fantastic!