I put the Who? in Mishehu wrote: > > I would like to use transcode to encode this file into a matroska (mkv) > container with h.264 as the video codec and a direct copy of the audio > (no transcoding of the a52 stream). There are three options that I know > of so far: > > 1. Use transcode selecting x264 as the video codec for -y > 2. Use transcode specifying ffmpeg as the backend > 3. Directly using ffmpeg and skipping the use of transcode. > > I would like to try 2-pass encoding for best overall quality. The > expense of encoding time is of no real consequence to me, as I can > simply batch these up and run them overnight.
According to the x264 developers, 2-pass is non-functional in x264. The passlog file, according to them, contains only null entries. There is some sort of aggressive lookahead option for x264 called cpb or something (I don't do x264) that they CLAIM does as good as 2-pass but in a single pass. My own observations of many people's encodes indicate that it is easy to do a high-quality encode with x264 that is not as good as a high-quality encode done with lavc mpeg4. A real expert however can do a mind-bogglingly great encode with x264. If your content has any high-action, check the results with x264 carefully, because that's where it falls down (and that's exactly where lavc 2-pass shines).
