Bluray rip on MKV, Avidemux recompress with x264 -> Audio out of sync

[sierramike]

Hi,

I am actually ripping my bluray discs because I want them to be played from NAS on my HTPC, and I don't own a BD drive on the HTPC (and don't want to, I have one on my laptop), also I want to choose my movies without having to step up and also my network isn't fast enough to transfer content at original bitrate thru the network.

So I need to compress them, I found the relevant informations on using Avidemux 2.5.6 (2.6 has a lot of greyed out options actually) to compress my videos using x264 codec. It is working fine, quality satisfies me. For the audio part, I demuxed the original m2ts file using tsMuxer Gui, to get the dts and dtshd tracks on separate files.

Then I mux the video with these audio files using mkvMerge Gui, setting the correct framerate on the video part.

Here starts the issue : when I playback, using MPC-HC or VLC, my audio is out of sync of values going from 40ms to 250ms depending on movies, on the last I tried yesterday, I hardly found 200ms/210ms delay, which at 23.976 fps means approx. 5 frames.

When I try to play the orignal m2ts file, audio is perfectly synced.

I try to resync by watching and adjusting delay by hand on each track, then remux the mkv putting the obtained delays, it works fine but :
1) It's much time consuming
2) It's done using my eyes/ears, not a scientific way ...

Is there any explanation about this issue and is there a way to avoid this out of sync ?

I remuxed original m2ts file to mkv using mkvmerge and it is synced, so the issue is only with recompressed video. It seems like Avidemux adds some fake frames at the beginning of the video which makes it a bit late compared to audio.

Any help would be greatly appreciated, as I'm yet bored about re-syncing manually after only ten titles, I can't imagine having to do that work on my whole discs ...

Thanks a lot !


P.S. : I tried Handbrake in the past but it doesn't show as much parameters to fine tune the x264 encoder, I spent so much time to get the appropriate parameters using Avidemux to get my best picture quality, I'd prefer to find out the problem !

[Baldrick]

I don't think avidemux is designed for any blu-ray m2ts shrinking....

Maybe try ripbot264 or megui and see if you can adjust more x264 settings.

[sierramike]

I gave a new try at last version of Handbrake and managed to apply command line parameters by hand on the x264 encoder, so it seems to become a good solution, I tried compressing 2 chapters for testing, and audio was in sync.

I suspect Avidemux's h264 decoder to send wrong frames to the encoder at the begining, so I'll change to Handbrake if I can apply the good parameters.