Mp4 containing h.264 720p video and 5.1 AC3 audio at 448kbps ... Should work?

I have a server full of files meeting the above spec (IMSA compliant streamable mp4s) that have been encoded and muxed specificly for use on a Tivo.  Will the WD TV Live play these files?  are there specific limitations or firmware revisions I need to be aware of to play these?  I really need to stick with one file format for both the Tivo and the WDTV Live so mkv is not an option.

The Live should play those MP4 files fine, with the limitation of AC-3 audio not being output as discrete channels (downmixed to stereo).

The MP4 specification did not originally support AC-3 but I’m no longer certain that is the case.

Regardless, you won’t get true surround sound support while using MP4 or M4V on the Live or Plus (that’s been my experience when using Optical-out into a Pioneer AVR).

Unfortunately, MKV is the safest option, yet not an option for you. You might want to look elsewhere, given there’s no timescale for a fix (Ideas Lab suggestion is here but has very few votes).

So the WDTV live will downmix the ac3 audio to stereo out the analog audio jacks but will not pass through the DD5.1 stream on the optical port?  Seems strange as the pass through support requires near zero development compared to the downmixing and conversion to analog.  What sound is passed over the HDMI cable?

Hard to believe it takes in a DD5.1 stream, downmixes to stereo and then re-encodes to either pcm or DD2.0 for the digital sound out.  What does it do with a DD5.1 stream from an mkv?  (same stream).

Since there really does not appear a better hardware player solution for my needs, guess I’ll put up with stereo output until WD fixes it or its addressed in aftermarket firmware.

Thanks for the info.  If anyone has any specific information on ac3 in an mp4 container for this device that does work in a specific configuration, perhaps I can find some overlap with the tivo requirements and make files that work for both if its a format or spec issue.

Sorry, I should have been more specific.

From an MP4, AC-3 (2.0 or 5.1) will be downmixed and output as stereo PCM via analogue and / or digital connections (depending on how you how it set up).

From an MKV, AC-3 (2.0 or 5.1) will be output as AC-3 (AVR lights up to show discrete channels are being received as expected, whether they’re 2.0 or 5.1).  That’s via digital; analogue will be stereo.

I have MP4 and M4V files that I’ve remuxed to MKV (keeping the original MP4 / M4V for reference), so I’m testing with the exact same streams, just different containers.

I agree that it seems like WD have made unnecessary work for themselves by downmixing the AC-3 streams in MP4.

Looks like the PCH players don’t support AC-3 in MP4 either, even though there are plenty of posts on the forum linking to the latest MP4 spec (couple of years old, still not implemented).

It’s not really the Live’s fault – MOST players (even including the developer of the MP4 format, Apple) don’t support 5.1 surround sound.  The MP4 format is ill-defined in this regard.

Add in the fact that MP4 doesn’t support DTS at all and it’s clear it’s an obsolete format.  Still, I do understand you wanting to keep both.  I have a TiVo and that’s the way I started – then I realized it was silly to play files on the TiVO when a media player like the Live did it MUCH better.  My TIvo units are now firmly relegated to what they do best (record and play what they record) and the Live handles what IT does best (play all other media file formats).

In an ideal world you could use only one device for everything but I’m afraid we’re at least a decade away from that (if ever).

PixelPower wrote:


From an MKV, AC-3 (2.0 or 5.1) will be output as AC-3 (AVR lights up to show discrete channels are being received as expected, whether they’re 2.0 or 5.1).  That’s via digital; analogue will be stereo.


Not fully true… :wink:

At least with the last official FW, the live outputs AC3 2.0 as PCM stereo, even if the stream comes from a mkv file.

See here:



Thanks for all the input guys.  Don’t be so quick to dismiss the mp4 format though.  Its the native supported format for all apple devices, android devices, tivo, amazon VOD and netflix (last two in drm managed streaming containers).  I have no love for the format or in general things apple, its just the common ground that the hardware vendors support.  MKV is only popular in the internet underworld, not in any mainstream commercial form. 

Hopefully WD will continue development in this direction with Apple, Google et al pushing the standard.  Not like there is a better option at the moment.

Actually, I’m more dismissive of the MP4 format BECAUSE of Apple (and I’m an Apple Level 4 forum guy). 

The format is old and nearly obsolete in terms of capabilities – of course Apple (notoroiously old-fashioned when it comes to advancements, which most people don’t realize: the iPhone being a prime example) doesn’t really care that DTS and high HD isn’t supported.  If/when it’s ever added it will mean more work for them (and devices they make that it won’t work on).

I’ve given up on MP4 (and I have iPhones, and Apple TV up the ying-yang) and most others have as well.  MKV is the container of choice for the future.