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Tegra 3 Does not support AC3 Audio

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Digital Man

Senior Member
Jul 21, 2007
318
63
New York
Tegra 3 Does Not Support AC3 Audio


Despite what everyone has assumed, there apparently isn't any AC3 support at all in Tegra 3. In other words, HW accelerated audio in an MKV
isn't even possible. Basically, NVIDIA gave us high profile video with no audio!

NVIDIA Tegra 3 Audio Support Specifications:
Decode

AAC-LC
AAC+
eAAC+
MP3
MP3 VBR
WAV/PCM
AMR-NB
AMR-WB
BSAC
MPEG-2 Audio
Vorbis
WMA 9
WMA Lossless
WMA Pro
G.729a *
G.711 *
QCELP *
EVRC *

* Through third party



Encode

AAC LC
AAC+
eAAC+
PCM/WAV
AMR-NB
AMR-WB

Notice that there is no mention of AC3 support!


Here is the link if you wish to check the specs yourself: http://www.nvidia.com/object/tegra-3-processor.html


The TF Prime, TF300 and Toshiba excite are all handicapped when playing video containing AC3 audio, such as just about every MKV.

The tf300 cannot play an MKV with audio in the built-in audio player. The video plays silent.
MX Player cannot play an MKV with HW audio. You must select software audio or else the video plays silent.
Only Dice Player can play an MKV with sound.

But, I suspect that dice player simply defaults to its own software audio and is NOT using HW audio acceleration.

The Acer Iconia on the other hand, has licensed Dolby Audio on board, and I suspect, has added codecs supplied by Dolby. It is my guess that THIS is the

reason the Iconia can play MKV's correctly.

It can play an MKV with audio in the built in player.(ASUS tf300, TF Prime, and Toshiba excite cannot)
It can play an MKV with audio in MX Player WITH HARDWARE AUDIO SELECTED! (ASUS tf300, TF Prime, and Toshiba excite cannot)
It can play an MKV with audio in Dice Player. (ASUS tf300, TF Prime can also do this because Dice apparently supplies SW audio by default.

Take away message:

Only the Acer iconia a510 has AC3 support across the board and can universally play MKV AC3 audio.

All other Tegra 3 tablets are at the mercy of the 3rd party video players and their supplied software AC3 support.

Of course in the real world, this may or may not be important to you. It is certainly possible to play MKV video quite well in Dice player on all of these tablets. However, if 3rd party support for your chosen player fails, you must understand that the built in players in these tablets will play silent with most MKV files. Only the iconia a510 does not rely on a 3rd party player for MKV playback.

As a disclaimer, I own both a Transformer and an a510 so I have no personal bias toward either. I am quite fond of both, and both have their pros and cons.
 
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Digital Man

Senior Member
Jul 21, 2007
318
63
New York
Supersoulfly: Quoted from previous thread,

Perhaps someone knows, was AC3 a problem with Tegra 2 also?

I personally am using the BS Lite player to get my MKVs to work. If Nvidia dropped the ball on this I don't see any other solutions than outside software.
--------------------------------------------------------------------------------------

Yes it was. In fact myself and I believe another member, emote were responsible for long threads showing how to split MKV files into two parts, remove the audio, convert to another format and put them back together. The objective was to avoid having to transcode the video. Tegra 3 is much better, because at least it can handle the high profile video well, and it has the software horsepower to do the AC3 decoding. Just seems that the problem really shouldn't exist at all at this point.

Course the next thing I would be curious to know, is if exynos or snapdragon processors support AC3. If they do, it might bias me toward them in the future.

The Transformer Infinity is rumored to have (or will have) multiple processor choices. I know I would be inclined to chose the processor that supports AC3 as well as high profile video, so that MKV files just play without all the software workarounds.
 
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supersoulfly

Senior Member
Dec 29, 2010
357
168
Seoul, Korea
I'm not too interested in the infinity yet. Really would like to see how well the Tegra 3 (or snapdragon) runs at that high resolution first. That high resolution is new territory for Android and ICS, not sure how app friendly it will be either.
 

Digital Man

Senior Member
Jul 21, 2007
318
63
New York
Just a random thought, but I would guess it has to do with licensing fees.

Of course it has to do with licensing fees.

But can you imagine buying a Blue Ray player or Reciever that can't decode Dolby soundtracks?

Dolby digital is a pretty common format.

And when you call the company to complain that your blue ray player or reciever won't play audio, they tell you to get an external decoder for the audio, our players just handle video?

If you question the importance of their decision, ask yourself:

Why did Acer think that it was so important to get Dolby audio onto the a510? Why did Acer pay the licensing fees that NVIDIA didn't? Because someone at Acer realized that the video player on the iconia can't play any videos. And the first thing the customer is going to do when he gets home is to dump the latest episode of his favorite TV show on his Acer tablet and see how it plays. And on the Acer a510 it actually does! So why was Acer able to think through what the customer wants, and NVIDIA unable?


Remember NVIDIA is not a small outfit. They make computer gaming chips that are designed to play and support just about everthing. To not support a codec that is present in just about every downloaded movie on the planet is strange. But remember this is the same company that designed a chip, the Tegra 2, that couldn't even play high profile video. I had to transcode every movie or TV show that I played on my galaxy tab 10.1 since the day I bought it.
 
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Digital Man

Senior Member
Jul 21, 2007
318
63
New York
I think you are misunderstanding. There isn't anything wrong with MKV playback on these tablets. Dice Player works well on both the TF300 and the a510.

The point is that, the absence of audio in some players, like the stock player in the TF300 or the HW audio option of MX Player has always been assumed to be due to a fault in the video player not using the HW audio decoding capability of the NVIDIA tegra 3.

I'm just pointing out that missing hardware audio - or missing audio altogether in some of these players is because there ISN'T any ability at all in the tegra chip to decode these soundtracks. If the programmer hasn't implemented a software decoding solution, you will get no audio.

Dice Player has a software solution, it decodes AC3 and you get sound.
MX Player has a software solution, you select it manually and you get sound.
The stock player depends on Tegra 3, therefore you get no sound in your video.

The a510 has a system-wide fix for the NVIDIA's lack of decoding capability. Acer paid dolby to implement the decoding that should have been native to our tablets, so any video player will work. Even the stock player.
 

BierLiebHaber

Senior Member
Aug 21, 2011
62
8
Berlin
I'm guessing nvidia didn't include dolby digital because it would be quite pricey to license it and they want to get as many companies to use their chips as possible
so they didn't include it but if companies themselves license dolby digital they probably provide hw decoding
 

mendez84

Member
Jun 20, 2011
16
1
Massachusetts
Well about the audio AC3 , its does play Ac3 , about 2 days ago i saw a movie with ac3 audio and works fine, you only need to download the BSplayer lite and will play all formats ...

Sent from my ASUS Transformer Pad TF300T using xda app-developers app
 

EndlessDissent

Senior Member
Oct 18, 2010
3,373
958
Chicago
Well about the audio AC3 , its does play Ac3 , about 2 days ago i saw a movie with ac3 audio and works fine, you only need to download the BSplayer lite and will play all formats ...

Sent from my ASUS Transformer Pad TF300T using xda app-developers app

Yes, you can hear AC3 audio from this tablet. The thing is, it's being decoded via software, not the actual SoC. That is the OP's gripe. Hardware decoding requires much less work for the processor, which means better battery life. Plus, it would be much smoother and more consistent than software decoding.