7.1 DTS-HD MA copies incorrectly?

[etrask]

Hello all. A while back when I was exploring the issue explained here, I've actually noticed something odd.


I have several blu-rays that have audio in 7.1. Most of these are encoded DTS-HD MA, one is encoded straight LPCM. In the thread above it was concluded the strange channel layout made it difficult to convert from DTS-HD to FLAC. So to investigate my options with converting with another tool, I had MakeMKV just mux the DTS-HD MA track into the output. Strangely, even just copying the stream resulted in a 5.1 audio track! ffprobe showed:

Stream #0:2(spa): Audio: dts (DTS-HD MA), 48000 Hz, 5.1(side), fltp, 1536 kb/s
Metadata:
title : Surround 7.1

For some reason, 2 channels were not making it to the output.


Wanting to eliminate the possibility that this was due to the strange layout, I looked for other discs that had 7.1 audio. I found that the TV show Weeds season 2 was released with 7.1 LPCM, and season 3 was released with 7.1 DTS-HD MA. I used MakeMKV's "Default" conversion profile to rip an episode from each, selecting every possible thing to mux into the output.


The season 2 episode seems to copy the 7.1 LPCM audio correctly. mkvinfo shows the track codec ID as "A_MS/ACM" and ffprobe shows:

Stream #0:1(eng): Audio: pcm_s16le ([1][0][0][0] / 0x0001), 48000 Hz, 7.1, s16, 6144 kb/s (default)
Metadata:
title : Surround 7.1

The season 3 episode has the same issue the blu-ray with the odd layout had: it seems to throw away channel data. ffprobe shows:

Stream #0:1(eng): Audio: dts (DTS-HD MA), 48000 Hz, 5.1(side), fltp, 1536 kb/s (default)
Metadata:
title : Surround 7.1

I suppose this could be a limitation in ffmpeg's ability to utilize DTS-HD MA (either while muxing it from MakeMKV or while examining the file afterwards). I'm using MakeMKV 1.8.13 x64 on Linux. It's compiled against ffmpeg 2.3.3, ffprobe is from that same compilation. Unfortunately I don't have any 7.1 TrueHD discs, to see what that might do.

Is there an error, with 2 audio channels getting thrown away? Is ffprobe simply mis-reading the files? ffmpeg supports 7.1 audio according to here. I don't know what's wrong here...

Any help is appreciated, if I've left out important details I'll do my best to provide them.

[The Masked Onion]

If FFprobe is reporting that bitrate for the DTS-MA stream then it's just reporting on the DTS stream. try using EAC3TO to check the file.

[etrask]

That seems to be what was happening... when I extract the DTS-HD MA track using mkvextract v6.7.0 and pass that output to eac3to 3.27 it shows:

E:\eac>eac3to.exe Weeds_S3_test.dts
DTS Master Audio, 7.1 channels, 24 bits, 48kHz, dialnorm: -4db
(core: DTS, 5.1 channels, 24 bits, 1509kbps, 48kHz, dialnorm: -4db)

eac3to also informs me that libav can't decode HD DTS tracks (for the life of me I couldn't get it to use ArcSoft's DLLs).

It seems when I use the "FLAC" profile, MakeMKV can successfully convert the track to 7.1 FLAC (except on the Pan's Labyrinth blu-ray, as linked above).

That settles that then, thanks!

[The Masked Onion]

BTW the problem with converting DTS-MA 7.1 to FLAC should now be fixed. Just make sure you are using the latest version of dtsdecoderdll.dll as explained on this page (/dtshd/).

Download and install Arcsoft TMT player (http://www.arcsoft.com/totalmedia-theatre/) don't run the software just search the install folder for dtsdecoderdll.dll and copy it in to your makemkv folder and change the MakeMKV preferences, advanced tab and point it to the location of dtsdecoderdll.dll.

[etrask]

BTW the problem with converting DTS-MA 7.1 to FLAC should now be fixed. Just make sure you are using the latest version of dtsdecoderdll.dll as explained on this page (/dtshd/).

Download and install Arcsoft TMT player (http://www.arcsoft.com/totalmedia-theatre/) don't run the software just search the install folder for dtsdecoderdll.dll and copy it in to your makemkv folder and change the MakeMKV preferences, advanced tab and point it to the location of dtsdecoderdll.dll.

I'll give that a shot when I can, thank you.

I believe the problem with Pan's Labyrinth (specifically) was that it used a strange channel layout that wasn't specified in WAVEX, or something like that. But I'll try again and see what success I have.