"fit to a cd" button

[David Prieto]

Hi,

I have lots of problems calculating the exact quality I should give to a video. I don't want it to look crappy in the end, but I wouldn't feel well thinking that I'm wasting disc space on videos that could look just as good and be lighter.

Also, I can see myself wanting to rip a DVD in order to transfer the resulting file to a CD. Could we have a "fit to a CD" button that would calculate the optimal video and audio quality settings for a 700 mb output video? Maybe even "fit to size", so that the user can select the desired filesize?

As with the other request, I understand this might be out of the original intended features so if you think that it would overcomplicate the interface or just that it is not suitable, please feel free to close the report.

[Jason Gerard DeRose (jderose)]

The great thing about the quality modes is that you don't have to worry about trying to guess what size is best. The idea with the quality setting is that it corresponds to a level of perceived quality, and the codec then uses whatever bit-rate is required to deliver that perceived quality for each small interval. Both Theora and Vorbis have sophisticated quality-based, variable-bit-rate encoding modes.

So my advice is to decide what level of perceived quality you want, and then to stick with it.

You'll noticed that the file size for, say, an hour of video will vary substantially from movie to movie. Using a quality based, variable bit-rate encoding like this is the only way to ensure that you are both (1) getting consistent quality and (2) getting the lowest *average* file size possible.

The only strait foreword way to get a Theora video to fit within a certain file size is to use the fixed bit rate mode, which delivers a poor results for a given size compared to the quality mode.

Also, by default KungFu currently encodes at full DVD resolution, which few rippers do by default, so keep that in mind if the file size seems too large. No current codecs can encode a typical feature length (2 hour) movie at full resolution and make it fit on a CD... without it looking like crap. This is true for Xvid and H264 (what iTunes uses).

To approach DVD quality, expect at least 10 MB per minute... so about 1.2 GBs for a 2 hour movie.

I'll probably still add a fit to CD button at some point, but I'm trying to encourage people not to rip that way in general. I really have building a video library on one's hard drive in mind with KungFu, for which the quality mode is by far superior.

Anyway, ramble ramble ramble... ;)

[David Prieto (frandavid100-gmail)]

Thanks for taking the time to explain it so thoroughly, Jason. I still think that on *very* specific situations a fit-to button would be desirable, but I will try to get into the "video library" mindset.

By the way, there's something I've been thinking about lately: can KungFu create videos with two language tracks? That way I could keep a single file to watch the movie in Spanish (if I want to watch it with my girlfriend, for example) or in English (if I want to practise my English).

Is that even feasible? And is it worth filing a bug?