qaac - a new command line AAC/ALAC encoder using QuickTime API

[SeeMoreDigital]

Originally Posted by kentafilo

Hello everyone.
I would need your opinion regarding an audio encoding.
In your opinion, starting from a DTS Master Audio file, if I wanted to transcode it, would I get a better quality file with qaac encoding at vbr 127 kbit/s or with AC3 at CBR 192 kbit/s?

I think you mean 're-encode' not "transcode"... Also, is your DTS-HD MA source stereo or multi-channel?

[kentafilo]

Yes exactly, I meant "re-encode"
The source file is a DTS -HD MA stereo

[SeeMoreDigital]

Originally Posted by kentafilo

Yes exactly, I meant "re-encode"
The source file is a DTS -HD MA stereo

Personally, I would re-encode any 'lossless' stereo source to flac.

But much will depend on your given audio playback device(s). Is there any particular reason why you want to encode 'lossless' audio to 'lossy' audio?

[kentafilo]

"I have carried out a personal project and re-encoded the DTS-HD MA audio into an MP4 using the qaac encoder (version 2.80). An acquaintance criticized my choice, stating that in such cases, it is better to re-encode in AC3 and that the audio quality of AC3 (192 kbps) is superior to that of AAC (qaac VBR 127 kbps). I would like to point out that the original audio file, even though in DTS-HD, is of poor quality. Given this, is it true that AC3 is better than AAC?"

[microchip8]

No. AC3 is not better than AAC, especially at lower bitrates

[SeeMoreDigital]

2-channel 'lossy' Dolby Digital is not as good (efficient) as lossy LC-AAC or HE-AAC. However it is useful if you are bit-streaming such audio to an external decoder amplifier!

But like I said earlier... Is there any particular reason why you want to encode 'lossless' audio to 'lossy' audio? What playback device(s) are you using?

[tebasuna51]

Of course if the sound track have good quality (not only lossless but high frequencies without noise) recode stereo DTS-MA to flac can save space with the same quality.

But if the sound track is from a old movie most the times a lossy encode is enough, I recommend use qaac -V 90 or 100 much better than AC3 192 CBR.
A make a test over the movie "Daddy Long Legs", even with many music included, and I obtain:

VBR min./avg./max. : 6 / 118 / 383 Kb/s (for -V 90)
VBR min./avg./max. : 6 / 132 / 406 Kb/s (for -V 100)

Like you can see when qaac need more quality use high bitrates much better than 192 CBR, but with silences and dialogs don't need so much and the bitrate average is less than 192 CBR

Using CVBR -v 128 I obtain VBR min./avg./max. : 6 / 115 / 376 Kb/s
I recommend TVBR -V instead -v CVBR because we don't know the bitrate needed, it is better, for me, fix the quality.