Digital TV Audio - Is AC3 better? NICAM - How do I get Track1 to Track2 ?

[jksmurf]

We got digital DMB-TH at last (well in my area), so apologies for all different threads but I thought they were all new subjects .. :-)

Anyway, for some reason the channels thrown up are just plain e.g. "Pearl" and "Pearl AC3". As noted in my comment in a thread from Feb 2008:

Code:

Related technologies
In October 2007, both broadcasting companies had agreed in November 2007 to utilize [url=http://en.wikipedia.org/wiki/MPEG2]MPEG2[/url] video format for [url=http://en.wikipedia.org/wiki/Simulcast]simulcasting[/url] channels (TVB Jade, ATV Home, TVB Pearl and ATV World), and the [url=http://en.wikipedia.org/wiki/H.264/MPEG-4_AVC]H.264[/url] format will be implemented for all digital broadcasting only channels [url=http://en.wikipedia.org/wiki/DMB-T/H#_note-3][4][/url]. For the audio codec, usual DTMB [url=http://en.wikipedia.org/wiki/Set-top_box]set-top boxes[/url] will support [url=http://en.wikipedia.org/wiki/MPEG-1_Audio_Layer_II]MPEG-1 Audio Layer II[/url] (MP2) for [url=http://en.wikipedia.org/wiki/Stereo]stereo[/url] audio tracks, and [url=http://en.wikipedia.org/wiki/Dolby_Digital#Dolby_Digital]Dolby AC-3[/url] for [url=http://en.wikipedia.org/wiki/Surround_sound]surround sound[/url] audio tracks.

Q1. So I guess the plain ones are MP2 and the other ones Surround Sound AC3?

The funny thing is the AC3 Filter Icon come up when I play back, even though I did not choose the AC3 Channel? Taking e.g. the Channel that has Pearl and Pearl (AC3) the attached is stream details from the TS file using just plain Pearl.

Q2. I guess this could be because "A/52 (A52) is essentially the same thing as AC-3 (AC3)". SO why would one be non-AC3 but has essentially AC3 audio and one is stated as AC3? Odd.

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Q3. NICAM. When I play the recorded TS file via GBPVR I get Chinese but when I play the recorded TS file in WMP I get an English Track (I can select the Chinese one in WMP which is track 2). So how do I get the English one in GBPVR? I tried Ctrl-G as per the WIKI but no joy? How do you toggle the audio Track?

Thanks!!

k.

k.

[mvallevand]

ATSC A/52, AC-3 and Dolby Digital are the same. Looking at your VLC it simply looks like you old text description is wrong you are getting stereo in AC3. I can't help with the PC, but if you still have your PCH mvpmcx2 should default to playing English tracks (the default can be changed)

Martin

[pBS]

i believe thre is a default language setting in config.xml you might wanna check...
it also may have something to do with your windows region settings..
oh and ac3/a52 usually sounds better than mp2 and many times mp2 isn't multichannel, only stereo..

[jksmurf]

i believe thre is a default language setting in config.xml you might wanna check...
it also may have something to do with your windows region settings..

OK, will give that a whirl. Not sure how those setting knows the language I want is on Track 1 or Track 2, but won't hurt to try it! I wonder how the PCH does it - anyway I'm glad it does, although it would be nice to toggle it on the PC in case they swap them around.

Cheers
k.

[mvallevand]

The mvpmcx2/PCH logic gives first priority to the English or default language, then to ac3, mpeg, and aac and finally he-aac You can switch with the audio key

Martin

[jksmurf]

OK I looked in config.xml but it seems only for GBPVR, not audio streams. I'd really like to see a toggle between audio streams when played on the PC, as sometimes it seems they NICAM Chinese audio in Track 1, other times in Tack 2. I'd like to quickly toggle to English each time. Any chance of a "quick fix"?


k.

[sub]

The next release has a mechanism to do this.

[jksmurf]

Yippee! Thanks sub!

[jksmurf]

The next release has a mechanism to do this.

sub - I guess this meant NPVR as the next release? WHat is the mechanism (keystroke?) (I use Ac3FIlter).

[sub]

Yes, NPVR records all the digital audio streams, and allows any of them to be the active audio during plaback. For now you have to right click and select the audio stream, but I'll add an audio toggle keystroke in the near future.