Video Format

[jayhon]

I put it in off topic because my query has nothing to do with Boxee or how it works, but more about creating video files that allow me to enjoy Boxee even more. By the way, if an mod sees this post BOXEE IS AWESOME!

Let me start with my setup:

Mac Mini C2D 2.0 / Optical Audio > Panasonic Receiver (The other components aren't necessarily important for this discussion)

I like the compatibility of the mp4 container but its apparent lack of *TRUE* AC3 audio output is a killer for me. At first I was happy to see my receiver automatically recognize that track as DDS (DOLBY DIGITAL SURROUND), but upon further inspection (VLC) that track is actually only 2ch not 6ch.

I know that MKV *DOES* support AC3 as well as multiple audio tracks which is helpful when the viewing does not require full DDS. This is nice, but MKV does not work well with almost anything, i.e. PS3 or PSP which are other viewing devices I use for various reasons.

AVI supports AC3 but one audio track.

Is there any way to make a mp4 (or m4v) container retain true AC3 6channel audio? What I don't understand is if you buy a movie from iTunes and watch it on your ATV you dont get true surround with your purchase?

I know, rambling, but it seems that MKV is my endgame here although I would love a little insight here.

[unisonband]

MP4 will support 6ch audio if it is encoded with AAC audio codec, fairly easy to encode an AC3 track to AAC, use foobar :) You will have H.264 video, 6 ch audio, and subs if you like. MP4 will never support AC3...

AVI will support AC3, but it had problems when mixed with h264 content.

MKV is your best bet for playing h264 with AC3 audio...in boxee it will play perfectly as well as long as the content is not 720P...I have played several MKV files and they all work great :)

Hope this helps :D

[jayhon]

As I had suspected, thanks Unison. Maybe some other members have some feedback too.

I have tried to used the AAC 6ch Discreet surround, the problem with that is that it encodes it in a format unrecognizable by many, if not all stereo receivers, including mine. If I am not mistaken, discreet audio means that the 6 channels have already been decoded and then the Mac Mini would need separate audio outputs for each channel (i.e. Front Left, Front Right, Center, Rear Left, etc.,)

This doesn't get me anywhere just wanted some more discussion points.

[ShavenYak]

MP4 will support 6ch audio if it is encoded with AAC audio codec, fairly easy to encode an AC3 track to AAC, use foobar :) You will have H.264 video, 6 ch audio, and subs if you like. MP4 will never support AC3...

This is not entirely true, you can put 5.1 AC3 audio in an MP4 container, it's just not an official part of the spec. Handbrake can do it, and some of the HD video purchased from iTunes is encoded this way. Plex, which is also XBMC based, can play these files, so I'd be surprised if Boxee can't. I'll have to test later.


AVI will support AC3, but it had problems when mixed with h264 content.

In addition to all its other problems. AVI needs to die already.


MKV is your best bet for playing h264 with AC3 audio...in boxee it will play perfectly as well as long as the content is not 720P...I have played several MKV files and they all work great :)

I've played 1080p MKV files in Plex on a first-generation Macbook (Core Duo, 1.83GHz), again I haven't tried on Boxee. Granted, I have to make sure absolutely nothing else is running, and once in a while it'll drop a few frames. 720p is fine.

What I really prefer about the MKV format, though, is that it's easier to work with. There aren't as many good tools to manipulate MP4 files, especially if you want to keep chapters/subtitles/multiple audio streams intact. Also, I can rip a DVD to an MKV and keep the video in MPEG2 and the audio in AC3 or DTS - no time-consuming transcoding or loss of quality.

[jayhon]

This is not entirely true, you can put 5.1 AC3 audio in an MP4 container, it's just not an official part of the spec. Handbrake can do it, and some of the HD video purchased from iTunes is encoded this way. Plex, which is also XBMC based, can play these files, so I'd be surprised if Boxee can't. I'll have to test later.

That is correct, Handbrake certainly THINKS it is using AC3 passthrough, but if you inspect the output file in VLC it says the AC3 stream is indeed only 2 channels. I think that the iTMS content is actually encoded as AAC Discreet 5.1, which is fine if you are using a ATV that has HDMI or analog RCA audio out. That won't play through the Digital Audio out of a Mini. Apple should open the container's ability to support it.


In addition to all its other problems. AVI needs to die already.

Agreed.


I've played 1080p MKV files in Plex on a first-generation Macbook (Core Duo, 1.83GHz), again I haven't tried on Boxee. Granted, I have to make sure absolutely nothing else is running, and once in a while it'll drop a few frames. 720p is fine.

What I really prefer about the MKV format, though, is that it's easier to work with. There aren't as many good tools to manipulate MP4 files, especially if you want to keep chapters/subtitles/multiple audio streams intact. Also, I can rip a DVD to an MKV and keep the video in MPEG2 and the audio in AC3 or DTS - no time-consuming transcoding or loss of quality.

I too will continue using MKV. Did my first test rip of Semi Pro and it works perfect, 720p and all. I know my Mini has a little more horespower than an ATV or Macbook so I think I'm set.