Which audio tracks should I keep?

[miceagol]

I'm ripping a concert blu-ray (Within Temptation - Black Symphony), which contains 5 audio tracks:

• LPCM 2/0
• LPCM 3/2+1
• DD 3/2+1
• DTS 3/2+1
• DD 2/0

mkvmerge -i output:

Code: Select all

Track ID 1: audio (A_PCM/INT/LIT)
Track ID 2: audio (A_MS/ACM)
Track ID 3: audio (A_AC3)
Track ID 4: audio (A_DTS)
Track ID 5: audio (A_AC3)

I'm not compressing the rip in any way, but I feel some of these audio tracks are a waste of space. Could you help me decide which not to keep?

The video is going to be played on many different devices (PC, iPad, TV, smartphone, etc.), so I'm not sure if e.g. the DTS track can be decoded on all the devices.

[ndjamena]

That's not a simple question. If you really don't want to keep all the audio tracks the best thing to do would be to keep the two PCM tracks (since they're lossless) and recompress them into compatible codecs on need. I'm pretty sure an iPad won't play an MKV without extra apps and you're not being very specific on what devices you're playing them on (Sony Bravia, Samsung, and which smartphone?) and how the files will be delivered (DLNA, External HDD). Is the Blu ray 1080p? The bitrate and size might be a bit much for some devices, so re-encoding may actually be necessary.

[miceagol]

Sorry, I'll elaborate.

I'm mainly going to play the rips through Plex. Plex will ensure that the rip is transcoded when played on the iPad/smartphones, so full size rip won't be a problem. These devices only need a 2.0 track, so I assume it's better to keep the PCM track over the AC3 track, since it's lossless? The same applies to PC's, but it'll be a mix of playing the files through Plex and VLC.

That leaves us with 3 5.1 tracks. Currently I don't have a 5.1 system connected to my TV, but the plan is to upgrade my 2.0 HiFi speakers to a 5.1 system soon. I will then buy a receiver which probably can decode all of the 5.1 tracks. So I assume the PCM 5.1 track is best to keep in this case? Do the DTS and DD tracks have anything to offer over the PCM track? I'd want the best possible quality when I play the rips through my TV system.

[Woodstock]

Not to mention that some audio tracks are NOT movie audio; the LPCM 2.0 is likely to be a commentary track.

Your choices are going to depend upon the movie and what your devices can handle. Unless you're using a high-end sound system, lossless vs lossy isn't going to matter much, in my opinion, and most of the devices you specified do not have particularly good sound systems in them.

Not to mention, you can ALWAYS re-rip if your needs change!

[miceagol]

Not to mention that some audio tracks are NOT movie audio; the LPCM 2.0 is likely to be a commentary track.

In this case it's not a commentary track.

Your choices are going to depend upon the movie and what your devices can handle. Unless you're using a high-end sound system, lossless vs lossy isn't going to matter much, in my opinion, and most of the devices you specified do not have particularly good sound systems in them.

The TV is connected to a high-end 2.0 sound system, and will be upgraded to a high-end 5.1 sound system. Thus, audio quality is priority #1. But I'd like to keep tracks that make playing the rips on any other device no hazzle.

Not to mention, you can ALWAYS re-rip if your needs change!

That is what I want to avoid, since ripping x number of discs is a lot of work in the first place (the concert blu-ray here is just one of the discs I'm ripping).

[Woodstock]

I can understand the want to avoid re-ripping if possible. I have almost 2 "Banker Box" cases of BDs to re-rip when I get a better solution to the PGS subtitle issue. If I had enough disk space, I'd keep the raw rips online for that day, but I don't.

As for the variety of devices, consider using a tool like Handbrake to optimize things by device. Using Handbrake to compress the video and store the "appropriate" sound tracks can make a lot of sense, at the expense of more processing time. For example, HB can compress a typical 1080p movie by 25% or more while still retaining very good quality for your TV, and create MUCH smaller files for your lower-resolution devices. The total space usually works out smaller than one MKV file, and the processor workload is reduced on playback. And saving as MP4 files increases the compatibility with many devices.

My personal usage has been reduced to two major Handbrake profiles - "High quality" for the TV, and "Android High" for everything else. For what I'm working on today, the raw MKV rip is 38GB; the "TV" version is 5GB, and the "Android" version (also works on iPhone) is just over 1.5GB.

[ndjamena]

Do the DTS and DD tracks have anything to offer over the PCM track? I'd want the best possible quality when I play the rips through my TV system.

The only advantages DD (AC3) has over PCM are the bitrate and compatibility. Any TV capable of receiving Digital Television can decode AC3 and anything that can play a DVD too. Traditionally, PCM has had too high a bitrate to be used for transport so many devices won't accept it despite the fact that they probably use it internally. If the TV (or attached Media Player) is capable of accepting PCM then there's no need for AC3, otherwise it's not hard to convert a PCM to AC3 (or AAC, or FLAC) later using eac3to or similar. As devices evolve, compatibility (and even bitrate) will become less and less of an issue. DTS has diddley squat over PCM and most of its advantages over AC3 are imaginary. Unless you want to keep tracks because they MIGHT feasibly be useful sometime down the track you should stick to PCM (and maybe even convert THEM to FLAC). If you listen to the two PCM tracks on a 2.0 system and can't tell the difference you might even consider ditching the 2.0 version as well, it depends on how well they optimised the sound for the speaker layouts. (I assume they are all the same, with no commentaries or other alternates).

If Plex lets you store videos on an iPad to watch on the go it may make handbrake redundant. Personally I've gone with the AVISynth, X264, Eac3to, NeroAAC, MP4Box route for my iPhone (with a lot of help from batch files and powershell).