DVD Encoding for Lossless

[lcphr3ak]

Hey,
From my understanding, the DVD format is already in the lossy mpeg-2 video format, as-well-as ac3 for the audio (please correct me if I'm wrong). I'd like to leave them in the quality as they are, but compress them; just like using FLAC or ALAC with audio (lossless). The problem I have is when I convert to something such as huffyuv or ffv1, the output is WAY larger than the original (probably more than 50 times bigger). Now, when I rip all the tracks of a CD to wav, and then encode those files to FLAC, there is definitely a huge difference in size, but the lossless is the one that is smaller. Essentially, I'm wondering if it is impossible for me to get a lossless codec that does nothing more than compress the format I have now, instead of fattening it up.

The software I'm currently using (because it's command line based) is ffmpeg. I've ripped the DVD to a single VOB file, so that's what I'm converting from. I've also (just in case) demuxed the VOB to M2V and AC3.

If there is any way to accomplish what I'd like to do, please let me know. Thanks for any help/advice in advance!

[jagabo]

Uncompressed full D1 video is about 112 GB/hr in RGB, 75 GB/hr as 4:2:2 YUV. Your MPEG videos are already hugely compressed (~4 GB/hr). Decompressing them then encoding losslessly will always get you a much bigger file.

The equivalent with audio would be to start with an MP3 file. Decompress it then compress losslessly. The result will be much bigger than the MP3 file you started with. When you rip an audio CD to WAV you are starting with uncompressed audio.

If you want to compress your MPEG video further you will have to use a lossy codec. Using MPEG2 and, say, cutting the file size in half, will give you significantly worse quality. Using MPEG4 ASP or AVC you might be able to shrink the file in half with very little loss of quality. But the result won't play on regular DVD players.

[Baldrick]

It's not possible. It would work if your source is uncompressed(HUGE) and you convert it a lossless format like huffyuv(still huge but smaller then uncompressed). But it wont work from an already compressed source like MPEG2 video.

If you want smaller size and keep almost same quality reconvert to for example xvid or h262 with mp3 or aac audio.

[lcphr3ak]

Ah, I understand now. I guess my understanding of the DVD format wasn't exactly on ball. Well, I'll have to play with different codecs and see what yields results to my liking. Thanks for the reply guys!