ac3 , acc or wma pro ?

[barty92]

i want to convert DTS (6 ch)

so what to choose ?
ac3 , aac or wma pro

i want best audio quality .

[thezanny]

AAC will be nice.
I read it that AAC in 320Kbps is sort of equal to 640Kbpsin AC3
But there's a small problem, AAC isn't supported by a lot of hardware products except for the Apple devices.

My choice is AAC

[hello_hello]

I generally convert to AAC. I use the NeroAAC encoder and it's default quality setting (0.50). You could always increase the quality but the default sounds fine to me. The average movie DTS stream is probably a bit over 1GB. Encoding it the way I do to multichannel AAC reduces the file size by around 600MB to 700MB.

In my experience, AAC is very well supported by hardware video players and even TVs with built in media players. At least where I live (PAL country). I'm yet to use a MP4/MKV capable Bluray player which can't handle AAC audio and neither of the media players built into the two TVs in the house have a problem with AAC. "DivX HD" certified media players must be able to decode multichannel AAC, AC3 and stereo MP3, if memory serves me correctly. DTS is optional.

[Mephesto]

AAC fer'sure. AC3 is as old as China, it sucks capital ass. Never use it if you can help it. AC3 is worse than MP3 at the same bitrate and AAC is almost twice as better than MP3.

At 320 kb/s it is high quality for 5.1 audio and with SBR you can go as low as 160-192 (-q 0.25) without audible loss in quality. I've encoded 5.1 audio tracks to as low as 96 kb/s with amazing quality (do NOT tweak the -q to force this kind of low bitrate, let it decide for itself.)

[jman98]

Anytime someone says "AC3 sucks" that is your proof positive that they are full of bs and do NOT know what they are talking about.

WMA pro is probably the least supported of the original 3 choices. I'm not saying it sucks. I'm just saying it will not be well supported because it is a licensed product and some manufacturers won't pay the license fees and thus won't support it.

I'm not particularly enthused about AAC as support is less than for AC3, but the original poster could just do a test and decide what he/she thinks for himself rather than posting and inviting people like Mephesto to pull stuff of his ass and act like it is scientific fact rather than his opinion. We've had posts here before from people who have to sign NDAs and work in the entertainment industry and they've said that there's nothing wrong with AC3. At high enough bit rates it can certainly offer excellent quality.

[Mephesto]

Anytime someone says "AC3 sucks" that is your proof positive that they are full of bs and do NOT know what they are talking about.

I'm not particularly enthused about AAC as support is less than for AC3, but the original poster could just do a test and decide what he/she thinks for himself rather than posting and inviting people like Mephesto to pull stuff of his ass and act like it is scientific fact rather than his opinion. We've had posts here before from people who have to sign NDAs and work in the entertainment industry and they've said that there's nothing wrong with AC3. At high enough bit rates it can certainly offer excellent quality.

MPEG-1 with MP1 audio at high enough bit rates is certainly excellent quality too, go use MPEG-1 and **** off.

Also, it is extremely common knowledge that AC3 at the same bitrate as MP4 (I hate calling it AAC) is noticeably worse quality. Several people have already done double-blind ABX tests, including myself and came to the same conclusion. Obviously DTS is high enough quality at 1536 kb/s but the OP still wants to transcode with another lossy codec, hmm..... perhaps the world doesn't revolve around you? Perhaps your wants are not the OPs wants?

Btw, only the uneducated and clueless say "scientific fact". There is no such thing. Look up the word "subjective" and find out why they call these subjective tests, 'tard.

EDIT: Here's your AC3 quality. Even at 256 kb/s for stereo it's not transparent. Pathetic.

[yoda313]

I'm not particularly enthused about AAC as support is less than for AC3,

I agree with this. At least as far as multichannel aac is concerned. At least with the ps3 I wasn't able to get a 5.1 aac track to playback on my older sd digital amp - output with fiber optic no hdmi inputs.

It may have changed now and newer hdmi amps may handle 5.1 aac just fine. I can't say for certain. But at least the few times I've fooled with it it doesn't seem to be a go on my setup.

I am more than happy with ac3 for its compromise of sound quality and file size. There are times were if its good enough for hollywood its good enough for me. Though I haven't bought a new dvd in awhile so I don't know if there are still new release action movies that are only ac3 and don't include a dts track.

[kingaddi]

I'm not particularly enthused about AAC as support is less than for AC3,

I agree with this. At least as far as multichannel aac is concerned. At least with the ps3 I wasn't able to get a 5.1 aac track to playback on my older sd digital amp - output with fiber optic no hdmi inputs.

It may have changed now and newer hdmi amps may handle 5.1 aac just fine. I can't say for certain. But at least the few times I've fooled with it it doesn't seem to be a go on my setup.

I am more than happy with ac3 for its compromise of sound quality and file size. There are times were if its good enough for hollywood its good enough for me. Though I haven't bought a new dvd in awhile so I don't know if there are still new release action movies that are only ac3 and don't include a dts track.

I also have an older sd digital amp. You mentioned that newer HDMI amps shoudl be able to handle 5.1 aac but, I don't see a lot of home threater amp support for aac. Do you know if the newer amps are able to convert aac to AC3?

[yoda313]

You mentioned that newer HDMI amps shoudl be able to handle 5.1 aac but, I don't see a lot of home threater amp support for aac. Do you know if the newer amps are able to convert aac to AC3?

Actually I said "may" handle. Since I haven't shopped for a new amp lately I don't know off hand.

However converting aac to ac3 is a relatively painless process. Demuxing and remuxing audio is generally fast (much faster than video on any computer). Using programs like eac3to is a great way to do it.

[kingaddi]

You mentioned that newer HDMI amps shoudl be able to handle 5.1 aac but, I don't see a lot of home threater amp support for aac. Do you know if the newer amps are able to convert aac to AC3?

Actually I said "may" handle. Since I haven't shopped for a new amp lately I don't know off hand.

However converting aac to ac3 is a relatively painless process. Demuxing and remuxing audio is generally fast (much faster than video on any computer). Using programs like eac3to is a great way to do it.

I will attempt to use eac3to today. My only concern with Demux/Remux is audio sync issues.

[yoda313]

My only concern with Demux/Remux is audio sync issues.

It certainly MAY happen. But you'll only know if you try. I think it would only be problematic with audio tracks that use variable bitrates (mp3 audio tracks mostly - don't know if other audio formats use variable bit rates or not). And again thats hit or miss but certainly is annoying when you do run into it.

You would need to post a separate thread on it if you encounter it.

[kingaddi]

My only concern with Demux/Remux is audio sync issues.

It certainly MAY happen. But you'll only know if you try. I think it would only be problematic with audio tracks that use variable bitrates (mp3 audio tracks mostly - don't know if other audio formats use variable bit rates or not). And again thats hit or miss but certainly is annoying when you do run into it.

You would need to post a separate thread on it if you encounter it.

I am guessing if I ran into audio sync issues after I could use Vegas Pro to realign it or is there a better method without recoding the video....

[yoda313]

I can't say off hand. I haven't had to deal with it personally in a long time. There is something called "offset" you can fiddle with. If you could find out what is numerically you can put that in a program and adjust it. However I'm not sure how you figure it out if its a visual thing you have to do yourself or if it can be analyzed by a program.

What I would do is go through your process first and then if you encounter it start a new thread detailing the steps you took.

Also gspot or mediainfo will tell you lots of detailed info about the internal structure of your source video file. That can be used to diagnose and possibly sort out your issues.

[hello_hello]

I am guessing if I ran into audio sync issues after I could use Vegas Pro to realign it or is there a better method without recoding the video....

What are you using for a media player? If it's a PC I'm fairly sure ffdshow will re-encode audio as AC3 "on the fly" and send it on it's merry way. I can't say I've ever tried it myself, but given AC3 encoding is extremely quick compared to other lossy formats (AAC, MP3 etc) I'd imagine it should work as advertised.

When it comes to re-encoding audio, if there's a sync issue afterwards it can generally be fixed by specifying an audio delay when replacing the original audio and remuxing. If it's one of those "mysterious" delays which appear to have no reason for being.....

I run the original video and the version containing the new audio in two instances of MPC-HC, and quickly stop and start one or the other until the audio of each is synced. You can tell when it's synced as rather than hear any delay you hear a phasing effect. Once the audio is synced I then watch the video for scene changes. If they happen at the same time the audio/video sync is the same. If not, I stop the video, use the + or - keys to delay the audio in one of the players, then play them both again, syncing the audio again etc.... Once the audio is synced and scene changes happen at the same time, I use the audio delay specified in MPC-HC's status bar as the audio delay to use while adding the new version to the existing video.

It can be a bit of trial and error to get it right, but I'm pretty sure the eye is fast enough to allow you to match the audio/video sync to within about 10ms.

[FulciLives]

Convert your 6 channel DTS to either 640kbps AC-3 or 448kbps AC-3

Even at 640kbps (the highest bitrate AC-3 offers) the file size is MUCH smaller than the DTS and MOST IMPORTANTLY you will NOT have issues playing it back since everything can play AC-3 and that just IS NOT so with 6 channel AAC

[fritzi93]

... AAC in 320Kbps is sort of equal to 640Kbpsin AC3
But there's a small problem, AAC isn't supported by a lot of hardware products...

1) Yeah, it seems to be the consensus that 320kps AAC is equivalent to 640kps AC3.
2) Support. There's the rub.

I'd just go with AC3 at 640kps and be done with it.