Going BELOW 32K For AAC+ Audio - Advisable?

Jeeper One · 19th January 2006, 17:56

Hi everyone:

I just realized that I didn't have AAC+ in my NSV Tools folder (or at least not properly inserted anyway).

Now that I do have it in there properly, I've been experimenting with the bitrates to get the best audio for the lowest possible bitrate. I tried bitrates in 32K increments beginning at 32K and working my way up to 128K.

Below are links to some sample videos (I'd attach one, but I've been down THAT road before!

) at the various audio bitrates I mentioned. The x264 settings were not changed, though the framerate was lowered to 23.97 as it seems as though my machine has problems with the current framerate setting of 29.97 which I have been using up to this point.

Video #1 @ 32K AAC+

Video #2 @ 64K AAC+

Video #3 @ 96K AAC+

Video #4 @ 128K AAC+

The audio BTW is in 44100 DUAL CHANNEL.

The goal is if I can lower the overall stream bitrate AND improve audio quality to make it sound even better than what it now, I figure why not go for it?

So...Opinions anyone?

Cheers

Pat (a.k.a. Jeeper One)

gaekwad2 · 19th January 2006, 18:14

Why dual channel? Is the audio bilingual (didn't try the streams)?

Below 48k I'd use Parametric Stereo, above Stereo (at 48 I'm still not sure).

sns2015 · 19th January 2006, 21:14

You can go as low as 28k (44.1k Paremetric) but you shouldn't ever need to go above 64k (44.1k Stereo). Also, if you go anything below 24k I would suggest lowering the sample rate to 32000, as 44100 seems a bit much for those bitrates. Dual channel forces the stereo stream into the two channels with equal bitrate for both (no matter what). This is your worst possible choice for low bitrate streaming. Use Parametric Stereo where available and real stereo when Parametric is not available. However, if you are to use AAC+ v1 (for VLC or whatever) I wouldn't go lower than 32k (44.1k Stereo).

Jeeper One · 20th January 2006, 00:26

Hi everyone:

Yeah, after re-ripping some vids promoting my favorite chat place (ActiveWorlds if you've ever been there) using 32/44 Dual Channel, they didn't sound bad, but they did leave me thinking I could do better (especially when you consider I'm using AAC+).

Also, with all the questions (both technical and legal) surrounding the use of x264 as a video codec, I think I'm just gonnna switch over to VP3 since there's NO legal controversy there AND it's stable. I've evben figured out how to keep the overall bitrate around 128K (if not lower) so there should be no technical issues.

So EFFECTIVE IMMEDIATELY, all my vids will be ripped in 128K VP3/32/44 Parametric Stereo AAC+. My current stream however will remain up until I have enough vids enoced to make the switch (I've got enough on the Hard Drive alone, but I just need to get them encoded).

This way, I don't get people who tune in and then immediately back out because they don't have the proper decoders and whatnot (come on AOL. Give us x264 within Winamp - PLEASE).

Cheers

Pat (a.k.a. Jeeper One)

slavas · 22nd January 2006, 13:05

Quote:

Originally posted by sns2015
... However, if you are to use AAC+ v1 (for VLC or whatever) ...

VLC have problem decoding PS, coz ADTS header says it's mono, when I patch AAC files as stereo and mux into nsv VLC plays them fine (nero's encoded PS AAC aready sets ADTS as stereo)

Daijoubu · 23rd January 2006, 16:45

I would either stick to 48k+PS or 64k Stereo

Btw, at 128kpbs, you may be better off using AAC, not sure how good is the Dolby encoder found in Winamp...
HE-AAC is optimized for lower bitrate (>= 96 I'd say)

Edit: but hum, why VP3 and not VP6? VLC comp?

mplayer > VLC

Jeeper One · 2nd February 2006, 02:42

Hi everyone:

Well...No matter which way I go with the video (VP3 or x264 - I'm now undecided on that), I have decided to go with 32K AAC+ Parametric Stereo if for no other reason than to keep the bitrate and (ultimately) the filesizes down to manageable levels.

Cheers

2nd February 2006, 02:42	#7
Jeeper One Major Dude Join Date: May 2003 Location: Denver, Colorado Posts: 1,055	Hi everyone: Well...No matter which way I go with the video (VP3 or x264 - I'm now undecided on that), I have decided to go with 32K AAC+ Parametric Stereo if for no other reason than to keep the bitrate and (ultimately) the filesizes down to manageable levels. Cheers Pat Cook Englewood, CO

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19th January 2006, 17:56	#1
Jeeper One Major Dude Join Date: May 2003 Location: Denver, Colorado Posts: 1,055	Going BELOW 32K For AAC+ Audio - Advisable? Hi everyone: I just realized that I didn't have AAC+ in my NSV Tools folder (or at least not properly inserted anyway). Now that I do have it in there properly, I've been experimenting with the bitrates to get the best audio for the lowest possible bitrate. I tried bitrates in 32K increments beginning at 32K and working my way up to 128K. Below are links to some sample videos (I'd attach one, but I've been down THAT road before! ) at the various audio bitrates I mentioned. The x264 settings were not changed, though the framerate was lowered to 23.97 as it seems as though my machine has problems with the current framerate setting of 29.97 which I have been using up to this point. Video #1 @ 32K AAC+ Video #2 @ 64K AAC+ Video #3 @ 96K AAC+ Video #4 @ 128K AAC+ The audio BTW is in 44100 DUAL CHANNEL. The goal is if I can lower the overall stream bitrate AND improve audio quality to make it sound even better than what it now, I figure why not go for it? So...Opinions anyone? Cheers Pat (a.k.a. Jeeper One) Pat Cook Englewood, CO

19th January 2006, 18:14	#2
gaekwad2 Foorum King Join Date: Jul 2003 Location: bar2000 Posts: 11,457	Why dual channel? Is the audio bilingual (didn't try the streams)? Below 48k I'd use Parametric Stereo, above Stereo (at 48 I'm still not sure).

19th January 2006, 21:14	#3
sns2015 Senior Member Join Date: Mar 2005 Posts: 218	You can go as low as 28k (44.1k Paremetric) but you shouldn't ever need to go above 64k (44.1k Stereo). Also, if you go anything below 24k I would suggest lowering the sample rate to 32000, as 44100 seems a bit much for those bitrates. Dual channel forces the stereo stream into the two channels with equal bitrate for both (no matter what). This is your worst possible choice for low bitrate streaming. Use Parametric Stereo where available and real stereo when Parametric is not available. However, if you are to use AAC+ v1 (for VLC or whatever) I wouldn't go lower than 32k (44.1k Stereo).

20th January 2006, 00:26	#4
Jeeper One Major Dude Join Date: May 2003 Location: Denver, Colorado Posts: 1,055	Hi everyone: Yeah, after re-ripping some vids promoting my favorite chat place (ActiveWorlds if you've ever been there) using 32/44 Dual Channel, they didn't sound bad, but they did leave me thinking I could do better (especially when you consider I'm using AAC+). Also, with all the questions (both technical and legal) surrounding the use of x264 as a video codec, I think I'm just gonnna switch over to VP3 since there's NO legal controversy there AND it's stable. I've evben figured out how to keep the overall bitrate around 128K (if not lower) so there should be no technical issues. So EFFECTIVE IMMEDIATELY, all my vids will be ripped in 128K VP3/32/44 Parametric Stereo AAC+. My current stream however will remain up until I have enough vids enoced to make the switch (I've got enough on the Hard Drive alone, but I just need to get them encoded). This way, I don't get people who tune in and then immediately back out because they don't have the proper decoders and whatnot (come on AOL. Give us x264 within Winamp - PLEASE). Cheers Pat (a.k.a. Jeeper One) Pat Cook Englewood, CO

23rd January 2006, 16:45	#6
Daijoubu Member Join Date: Jan 2003 Location: Montreal QC Canada Posts: 75	I would either stick to 48k+PS or 64k Stereo Btw, at 128kpbs, you may be better off using AAC, not sure how good is the Dolby encoder found in Winamp... HE-AAC is optimized for lower bitrate (>= 96 I'd say) Edit: but hum, why VP3 and not VP6? VLC comp? mplayer > VLC