Open Source Video Codec?

[privatehelmet]

I am running ubuntu 9.04.

I want to back up all my home videos which are on DVD. What would be a good video codec to use? I want to use an open source codec, preferrably lossless.

Thanks!

[rokytnji]

libdvdcss2 should be in your package manager.

also win32 codecs.

https://help.ubuntu.com/community/Re...ts/PlayingDVDs

[privatehelmet]

Please forgive me for being a total newb...

Are these codecs both open source? what is the file extension for files made with them?

I recently converted my entire music collection to .flac. I wanted to do something like that with my home videos.

[bigtomrodney]

You can use Ogg Theora as your video codec with Ogg Vorbis as the audio codec. These are both free, open source and without patent threats. The Xvid codecs are open source but there are patents that prevent this from being truly free - but bear in mind that the notion of software patents really only exists in the USA.

Now to throw a spanner in the works...all of the codecs you will install apart from the win32 pack are open source as such, but may not be free in the sense that they may infringe patents, the mp3 codecs being a prime example.

[privatehelmet]

If you use these two codecs, will there be two files (an audio and video file) or just one file (the video and audio combined)?

**I know that is probably a stupid question but I don' t know**

What is a spanner?

[bigtomrodney]

No, it'll be one file. Essentially when you rip a video you have a container file, e.g. .avi, .ogg etc. and then the data within is encoded using a codec - CODE/DECODE that is. The video stream uses a codec suitable for video and the audio has its own. This is the case with any rip. Most DVDs would be encoded using MPEG2 and have AC3 audio, the containers are VOB I believe.

On the subject of spanners, a spanner is what we call wrenches in my part of the world, we use the word wrench only for adjustable spanners/wrenches. However I was just using an old turn of phrase, meaning to make the problem worse when trying to help, i.e. to drop the wrench into the machine while trying to fix it

[privatehelmet]

First- Thank you so much for your response!

Is the container related to what codec is used for the video and audio data stored under that container? Or can any combination of video/audio codec be used under any container?

[D-cat]

It depends on the container. AVI is the most flexible as it can handle just about any codec for both audio and video. Its only major disadvantage is that the index block is at the end of the file, so it cant be efficiently used for streaming. For local playback, this is not a problem.

Other containers are often limited to some specialty. VOB is limited to MPEG2 video and mp2, ac3, or rts audio. WMV is limited to Microsoft codecs. The regular MPG containers are limited to mpeg video and audio (video can be 1,2, or 4, audio can be 1 layer 2 or 3 (mp2 or mp3, respectively)). The mpeg 1/2 codecs tend to make larger files than say xvid (which is a subset of mpeg 4) for the same quality, but are more universal and are designed to stream, thus more suitable for live media.

AFA lossless codecs are concerned, forget it. The only lossless encodings are effectively raw (DV, YUVx, etc), and the files are huge. As mentioned, DVD is MPEG2; it is a lossy codec, but you generally don't notice it. The question really is, how much compression can you apply and the loss not be noticeable? Different people have different answers to this one, but I generally find that if I use Mpeg4 video (Divx5,xvid) in constant quality mode of about 85%, I get decent compression and excellent quality, good balance for me.

Another tip, if you use MP3 as your audio format, use constant bitrate. Variable bitrate/constant quality mode for MP3 tends to cause audio/video sync problems with many players, at least that's my experience.