Audio Help

FlipperBizkut

[H]ard|Gawd
Joined
Sep 25, 2002
Messages
1,268
I soon plan to jump into the HTPC arena, and in preparation for this transition, I have decided to start converting my BluRay collection for storage on my hard drive. My ultimate vision for this project is having a nice little XBMC frontend with my movie collection available at the click of a button without the need to swap out discs and the such.

I have been throwing my BluRays into Handbrake for conversion. I am using h.264 at RF:19 in an mkv container. The problem I am having is with the audio. When given the options in Handbrake, I am selecting the DTS-HD MA track from the BluRay, and selecting DTS-HD Passthru as the audio codec. From my understanding, this will copy the DTS-HD MA track to the mkv unaltered from the original. In addition, the DTS core will remain in case the AVR can not handle DTS-HD MA.

When the encoding is done, however, all the software players I have tried (TMT5, VLC, PotPlayer), and my stand alone BluRay player all show only the regular DTS 5.1 instead of the DTS-HD 7.1. None of the players give an option of any secondary audio tracks either. The crazy thing is that the bitrate is well above 1500, so that leads me to believe that it has to be the DTS-HD track, but how can I be sure?

And then it gets even crazier with regards to Dolby TrueHD. Since the AC3 "core" isn't part of the TrueHD track, are you supposed to encode another audio track for fallback purposes? I have read that the "fallback" AC3 track is interlaced with the TrueHD track, but that the mkv container does not support that. I have also read that using mkvMerge will just ditch the AC3 track and keep the TrueHD track without even a warning. Then I come across SolveigMM_MKV_Muxer which is supposed to be able to include the TrueHD track with the fallback AC3 track interleaved within it just like on a true BlueRay.

I am totally at a loss. I don't want to encode two distinct audio tracks if it isn't necessary simply due to the extra size of the file that would necessitate. But I don't want to have just an HD track in case I grab the HTPC and take it to my sister's house who doesn't have an AVR that can decode the HD stuff (and I actually have an older AVR that doesn't do the HD stuff either, but will be replacing it soon). I was honestly thinking of just encoding the rips with the lossy audio, and if I wanted the "full experience," going and grabbing the actual BluRay disc and doing it that way. I don't know.

So I figured there were several of you guys that were doing this same thing, and I figured I would ask you to see what the best practice was before I go about encoding everything wrong and wasting all that time. I appreciate any insight you could provide.


tl;dr - I'm trying to rip my BluRay collection making sure to keep the HD audio intact, but also ensuring that there is "fallback" audio. I'd like to do this so that the appropriate audio is automatically selected, and prefer just a single track (like DTS-HD contains the DTS Core).
 
Sorry can't help with most of it but regarding playback - is your CPU/GPU capable of decoding HD audio tracks? I.e. what CPU/GPU are you using when playing on TMT5/VLC/PotPlayer, etc?

On your bluray player, how are you feeding the rip - HDMI? If so, do you have yout HTPC setup to bitstream the HD audio? Again - your CPU/GPU/mobo must be capable of bitstreamign HD audio. For bitstreaming, I use Shark007 codec pack which works awesome...
 
The encoding is being done in anticipation of building a dedicated HTPC. For now, playback is being done on my standard rig (i5 2500k). TMT5 shows DTS-HD from a BluRay source, but not from an mkv. I read that this is a limitation of TMT5 which prompted me to try the other players.

I am streaming the rip to the stand-alone BluRay player through Serviio. The BluRay player has an info box which shows the audio options, and there is no DTS-HD option at all. Just the standard DTS.
 
Sounds like your hardware is OK (I also have an i5-2500k). WMP will bitstream HD audio just fine with a codec pack like Shark007 (I do this through WMC).

I haven't used Serviio so can't help there - is that transcoding anything? In any case, WMP should suit you fine or you could also look at MPC-HC...
 
I don't believe you can use the 7.1 audio stream when encoding. AFAIK, you can only get 7.1 when playing the disc (or possibly an iso...) through playback software that also supports 7.1 - Cyberlink is the only one I know of off the top of my head. Once you can play 7.1 with software, then you can worry about bitstreaming it with Shark007.
 
I am streaming the rip to the stand-alone BluRay player through Serviio. The BluRay player has an info box which shows the audio options, and there is no DTS-HD option at all. Just the standard DTS.

Are you sure the Blu-ray player is capable of dealing with DTS-HD over DLNA? Sometimes the manufacturers do stupid things -- or have to contend with stupid licensing. Open the files up on your PC and see what FFDShow/XBMC say is really happening when they play.


My recommendation: Mux in as high-quality an audio stream as you feel the need for, then set XBMC to decode in software. Bitstreaming adds exactly zero fidelity over PCM. If you decode in software, you'll get 7.1 over HDMI, analog in as many channels as you're willing to plug in cables, and as for S/PDIF, XBMC (either in Eden or the nightlies, not sure which) has real-time AC3 transcode.

Personally, I wouldn't be overly worried about the lossless versions. I don't think codec stability is quite there yet, and we're so far into diminishing returns on audio quality that I don't think the lack will hurt overmuch. Unless you're going for future-proof rips, in which case, just suck it up and add the base AC3 track; next to the 18.64Mbit TrueHD and 24.5Mbit DTS-MA tracks, the 640Kbit AC3 at less than 300MB per hour is kind of a drop in the bucket.
 
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