Media format tests


#1

I mainly bought this device so I could play back my converted DVD and BD discs because my Linksys Media Center extender chokes on them. I use PavTube Ultimate for converting (it reads BD discs that most other software won’t), but the WD TV Live Plus has been having issues with playback on some of them, so I decided to do some testing to find out the best format for video and audio for my conversions. Here’s some of the results.

I used a clip from Avatar on Blu-Ray for all my tests. The WD TV Live Plus is connected to a 46" LCD via HDMI (direct) with its optical audio going to a Sherwood 5.1 receiver. Audio playback was determined by the indicator lights on the receiver (Stereo, Dolby Pro Logic, Dolby Digital, DTS).

Clip 1 - H.264 in an MP4 container. Audio in AAC 5.1 format.

Result=Video plays fine, no audio.

Clip 2 - H.264 in an MKV container. Audio in AAC 5.1 format.

Result=Video plays fine, no audio.

Clip 3 - H.264 in an MKV container. Audio in AC3 5.1 format.

Result=Video plays fine, audio plays in digital 5.1.

Clip 4 - Xvid in an MP4 container. Audio in AAC 5.1 format.

Result=Video plays fine, no audio.

Clip 5 - Xvid in an MP4 container. Audio in AC3 5.1 format.

Result=Video plays fine, audio plays in Dolby Pro Logic format (surround only, no subwoofer out).

Clip 6 - H.264 in a TS container. Audio in AAC 5.1 format.

Result=Video is slow to load, but plays fine. Audio plays in Dolby Pro Logic format (surround only, no subwoofer out).

Clip 7 - H.264 in a TS container. Audio in AC3 5.1 format.

Result=Video is slow to load, but plays fine. Audio plays in digital 5.1.

Clip 8 - MPG2 format. Audio in AC3 5.1 format.

Result=Video plays fine, audio plays in digital 5.1.

Considering that the WD TV is marketed as being AAC compatible, I’m at a loss to understand why it does not handle 5.1 AAC streams. It does support AAC stereo, but what is the point of downsampling a 5.1 movie to a stereo or Dolby Pro Logic soundtrack? Hopefully, this will be fixed in a new firmware. I’m also surprised that even though AC3 is not listed as being supported, it correctly outputs true 5.1 AC3 audio on the conversions that have it. All videos played smoothly and audio (sampled at 384kbps) was rich and room-filling. I wish the PavTube software would allow me to preserve the DTS soundtracks, but for less than $40 I might be asking too much.


#2

"Considering that the WD TV is marketed as being AAC compatible, I’m at a loss to understand why it does not handle 5.1 AAC streams. "

Are you sure that this isn’t a limitation of your AV receiver? Very few of them will decode AAC 5.1 streams. I have a Pioneer VSX 820 (good Boxing Day deal) which won’t decode AAC. The WD sends the AAC stream to the Pioneer, which happily ignores it. I have to transcode the AAC to AC3 to get “true” 5.1. 

Note, when transcoding, you have to get your channels re-mapped correctly, else you get your center coming out the left-front and the LFE out the left-surround. 


#3

Miami_Son wrote:

 

Considering that the WD TV is marketed as being AAC compatible, I’m at a loss to understand why it does not handle 5.1 AAC streams. It does support AAC stereo, but what is the point of downsampling a 5.1 movie to a stereo or Dolby Pro Logic soundtrack? Hopefully, this will be fixed in a new firmware. I’m also surprised that even though AC3 is not listed as being supported, it correctly outputs true 5.1 AC3 audio on the conversions that have it. All videos played smoothly and audio (sampled at 384kbps) was rich and room-filling. I wish the PavTube software would allow me to preserve the DTS soundtracks, but for less than $40 I might be asking too much.

For your DTS discs, if Pavtube can rip to an ISO (of if you use the free DVD Fab HD Decrypter to make an ISO), I believe you can then use Handbrake (also free) to make an MKV with DTS.

I don’t think the AAC 5.1 issue will be fixed any time soon.  The best fix would be for the Live to decode the AAC and output as PCM 5.1, with the downside that users connecting via Optical are left in the cold (not enough bandwidth in the S/PDIF spec for >PCM 2.0).  

The issue you found with MP4 not outputting AC3 is a known bug, WD are just taking their sweet time fixing it.

Very interesting that TS containers output AAC 5.1 as Dolby Pro Logic.  That’s the safest fallback and I’m surprised more containers aren’t doing that…

Like Warren, I re-encode any files with AAC 5.1 to AC3 5.1, which is usually a pretty fast process when using Popcorn MKV Audio Converter (free).  However, Warren’s comment about remapping channels has me wondering whether it does it properly… the films certainly sounded ok when I watched them…!!


#4

My receiver handles 5.1 AAC fine. I have a few discs with it and they output properly. I can always tell when the sub out is correct because my powered sub won’t turn on if there’s no signal present. Since AC3 decodes correctly I’m happy and will be keeping the WD TV. The added bonus of being able to watch Netflix online content makes it worthwhile. It’s interesting that the container used has a bearing on how the audio is handled by the WD TV. No MP4 setting will give true 5.1 for some odd reason. I’m going to try the ISO deal and see if that works. I did do a full disc copy to hard drive that preserves both the video and audio and it yielded an mts file with the entire movie in it that plays back on the WD TV with the DTS soundtrack, but the video bitrate is so freakin’ high that it stutters.


#5

“However, Warren’s comment about remapping channels has me wondering whether it does it properly… the films certainly sounded ok when I watched them…!!”

If the audio sounds correct, then it probably is. You’d certainly notice if your center channel was coming out front-left …

Your app probably knows to remap.