How can I convert a TRUEHD stream in a .mkv file to .ac3?

[bubbleboy11]

Hi,

I have a .mkv file with a TRUEHD audio stream. I want to convert the audio to .ac3. Is there a program that will do this automatically?

If not, I have managed to extract the audio and make a separate .ac3 file. How do I insert this into the now audioless .h64 file and rebuild the .mkv file and make sure it syncs up?

thanks!

BB

[Gew]

"Also, FFmpeg now has floating point PCM support and supports MLP/TrueHD decoding."ffmpeg.exe (http://ffmpeg.arrozcru.org/autobuilds/ffmpeg-latest-mingw32-static.7z) -i your.mkv -vn audiostream.ac3

[Adub]

Hi,
If not, I have managed to extract the audio and make a separate .ac3 file. How do I insert this into the now audioless .h64 file and rebuild the .mkv file and make sure it syncs up?


If you have extracted the audio and converted it to AC3, you can mux the audio and video streams back together using MKVToolnix.

[bubbleboy11]

Thanks ! I'll give it a shot! :thanks:

[bubbleboy11]

If you have extracted the audio and converted it to AC3, you can mux the audio and video streams back together using MKVToolnix.

I've managed to mux them together, but MKVToolnix tells me it doesn't know the FPS, so the audio is totally out of sync. Is there a program to check the FPS for a .mkv file?

thanks again!

[Guest]

[bump after re-open]

[joecody12]

you can try this video converter ，it cn meet your needs.

http://videotools.over-blog.com/pages/Aunsoft_Video_Converter-4758345.html

[ramicio]

The warning in MKVMerge you speak of is just some stupid error because the input can never detect the FPS of raw h.264 streams. You need to manually set the FPS in the "Format Specific Options" tab with your h.264 stream highlighted under the "Tracks, chapters and tags:" box. Otherwise it just blindly assumes the video is 25 FPS PAL.

[slipknot!]

Hi,

I have a .mkv file with a TRUEHD audio stream. I want to convert the audio to .ac3. Is there a program that will do this automatically?

If not, I have managed to extract the audio and make a separate .ac3 file. How do I insert this into the now audioless .h64 file and rebuild the .mkv file and make sure it syncs up?

thanks!

BB1. TrueHD already has ac3 audio in it as its core. Usually the core is 640 kbps.
=>
You don't need to convert truehd to get 640 kbps ac3, you can just extract it from truehd.
2. You can mux the video + audio into an *.mkv file using mvktoolnix, just don't forget to manually add the framerate. It's 23.976 fps for most Blu-Ray videos.

[ramicio]

TrueHD is not like DTS-HD Master where the codec itself is based around keeping a lossy core for decoders to fall back on. There can be TrueHD both with and without a AC-3 core.