ffmpeg -- stop that downmixing!

[grooveman]

Hi everyone.

I'm trying to rip my blu-ray collection so I can box up my blue rays and put them in cold storage and open up some space in the living room.

The only thing I found that did this with any elegance at all is makemkv. But, it doesn't really give you many choices. It pretty much dumps to one type of codec for video, and another for audio, and you are stuck with what it gives you. And, of course, my blu-ray player (which has dlna and can read files from smb/cifs shares on the network) does not recognize either.

So I am using ffmpeg to change the codec to mp4, and the audio to aac. The problem is, that every time I conver, say with a command like this:

[FishB8]

First, don't use mpeg4 for the video codec. Use x264.

Secondly, your video from the bluray is probably originally in h264 anyway, so you could just copy the video stream and re-encode the audio, which is probably in AC3. (Unless you are wanting to reduce frame-size, which would require re-encoding.

By default the audio channel count for the output is the same as the input, so I suspect your sources only has 2 channels of audio. Use ffprobe on the source to see what is inside it. Also, sometimes you can have multiple audio channels in the same source, so if that is the case ffmpeg might be mapping to a stereo audio stream by default rather than the 5.1/7.1 audio stream that you are wanting. If so, you have to explicitly map the audio stream correctly.
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[grooveman]

Thanks Fish.

Can you tell me a little more about the second option you mentioned?

What do you mean by "just copy the video stream"? And, as far as re-encoding the audio, I thought that is what I was doing... is that what you meant? If you are talking about just using the -copy for the video and audio codec, I have already tried that, and it produces unplayable results on my blu-ray player. Or are you talking about something else here?

Thanks!

G
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[darklegion]

Just a comment on your ffmpeg commandline: Don't use "-sameq" it's not same quality, it's same quantizers which probably isn't what you want: http://ffmpeg.org/trac/ffmpeg/wiki/Option%20%27-sameq%27%20does%20NOT%20mean%20%27same%20quality%27

And are you sure your blu-ray player supports mkv? You might try using MP4 as a container instead. The point about mapping the audio stream that Fish mentioned is essentially selecting the correct audio stream. I find the new method quite confusing as well, but it should be explained in the ffmpeg manpage.

Finally, copying means what is sounds like. It means copying the stream without re-encoding it, thus preserving quality and saving you the time and effort to re-encode.

[FishB8]