FLOSS Multimedia Support in Fedora

[Gregory Maxwell]

2009/2/9 Martin Sourada <martin.sourada at gmail.com>:
> Well, that is an interesting piece of software, but it seems to support
> either image subtitles (big, binary, suboptimal for most modern use
> cases) or purely text subtitles with none other effects than karaoke...
> Well, at least some positioning and basic styling (font, color, borders
> shadows) would make it an interesting alternative. Also there is AFAIK a
> lack to attach fonts to the stream to make sure the subs will look the
>same everywhere.
[snip]
> So basically we're left to amateur videos and screen-casts. In
> screencast at least subtitle positioning is vital to be able to use the
> subs effectively (you would not want to overlay your subtitles over some
> important text in terminal).

Pretty narrow view of the world! How about educational works,
government materials, porno, etc?  :) There are many things which are
no anime, pirated movies, amateur video, and screencasts. :)

In any case— you've missed what most of Kate can do. It is, in fact, a
bit overkill for most subtitling needs.

It can do positions, color, transparency, and even animate them with splines.

In fact, Kate's excessive flexibility in this regard is a problem
since it hinders adoption.

The font issue is somewhat hard: Fonts often have licensing problems,
they complicate seeking and dynamic access (big enough that you don't
want to constantly resend).

Kate is far from great, but it should meet most basic and many
advanced subtitling needs.

[snip]
>> I don't have tools to pick apart dirac streams as I do for Theora, but
>> I'd put money on your 'lossless' dirac only being a lossless copy of
>> the colorspace converted input.  Your RGB data was probably first
>> converted into YUV 4:2:0 which has lower resolution for the color
>> planes and can result in a slight loss of sharpness.
>>
> Yeah, I suspected something like that as well. I don't understand
> though, why you put the word lossless into quotes... There is an option
> in dirac compression to use lossless algorithm [1] instead of the lossy
> one. I rendered the video as well for private comparison, but due to its
> bigger size (IIRC it was 36 MiB) I haven't included it in my
> fedorapeople (also it's compatibility is same as that of the lossy
> dirac).

I used quotes only because you discovered that it actually wasn't
lossless for your input. :)

You'd probably have better results if you could force it into 4:4:4
mode, but I'd put money on the resulting files working in just about
nothing. :(