January 1st, 2010, 07:45 AM #1
Transcoding a DVD to mp4 (h.264) - Quality? Bitrate?
Hey guys I am in the process of updating my library so I can a. save some space, but mostly to get rid of the bothersome .vob, .ts files and be onboard the format of the future which undoubtedly h.264.
A few queries thus arise that I think might be in the mind of a lot of users here who are not that well versed in video codecs.
a. Quality. From a non purist pov, is there a significant decrease in quality in terms of transcoding a video, I have for example a few yoga dvds, will these take such a significant hit from the transcoding process? What material lends itself better to transcoding, and are there any settings to make sure that (despite maybe longer transcoding) times the material gets the best treatment possible?
b. Container format. Which one is the most fool proof in terms of future development, support by standalone media players etc. etc. I have heard some great things about .mkv, but I am willing to sacrifice quality to go with a more compatible format such as the apple backed .mp4. And having said that, how long until mainstream dvd players, or hard disk media players support .mp4 on a large scale. Will .mp4 be able to include dvd menu items etc. (I doubt it…and that is an issue).
c. Ok, we've all heard h.264 is more efficient but how much more efficient is it? Can someone provide a rough estimate, say 10% or 20%. Which of course translates to bitrate, is there a rule of thumb for it, so for example would a dvd or an mpeg part 2 (divx) bitrate translate to a 10-20% lower bitrate for h.264. How can one gauge that?
Any other pointers? Or recommended software for the mac?
I know handbrake, but why is it such a pain in the … to transcode dvds with it - it not recognizing (with my wrong settings perhaps) the structure and interconnection of the various .vob and .ts files.
January 1st, 2010, 10:37 AM #2
Handbrake is the best program I have used for converting. Handbrake also had many different presets for you to choose from for certain situation. I think will serve you well.
January 1st, 2010, 12:45 PM #3
I use handbrake but I have a hard time configuring dvd files to be recognized as one and split according to preferences, maybe I should re-read the manual. Also I d love to read somewhere about minimal/maximum performance/quality settings for transcoding.
January 1st, 2010, 06:01 PM #4
To get the best quality for a particular bitrate, you should either use one of the "constant quality" options (which will NOT let you accurately predict the size of the resulting file, but will give you the best overall quality for the size you end up with) or use two-pass encoding at the desired bitrate (which will take roughly twice as long to encode). Using 1-pass encoding with a set bitrate isn't the best idea, because low-complexity scenes will look great while high-complexity scenes will look worse.
There are several optional settings which can improve quality at the cost of encoding speed, playback performance, or both. Personally I don't mind how long a video takes to encode, since I only encode it once, but I like to keep the playback requirements as low as possible so I can play the file on a wide range of older/slower systems.
I recommend turning Trellis quantiziation to 1 or 2 and checking the "pyramidal b-frames" and "weighted b-frames" boxes. Each of these options should improve quality at the expense of encoding speed.
You can try increasing the number of B-frames as well, but be aware that this will affect not only encoding speed but also playback performance.
The Handbrake web site has a guide that explains many of the options: http://trac.handbrake.fr/wiki/x264Options
Personally I think around 1GB is reasonable for a typical movie, but it varies a lot based on the particular movie. If you don't need to hit a particular file size to, for example, fit X number of movies on a DVD-R, using constant quality set to about 80-85% should get reasonable results, and will be a lot faster than using 2-pass encoding.