DTS or AC3 as source?

[tomcat_]

I'm backing up a DVD movie in mp4 format using Megui.

When i have created a D2V file i got 2 audio files. One ac3 and one DTS almost double the size of the ac3.

I'm normally using NeroAAC to convert the sound and normally the multichannel one to keep the multichannel support.

My question is:

1.Shall i use the ac3 or dts as a source in audio input?

2. On the encoder settings shall i use the NDAAC-LC-multichannel or NDAAC-HE-multichannel?

I have read a few threads around here and the audio FAQ but it doesn't seem that i can find a clear answer on the above.

Thanks for your help

[nautilus7]

Normally, DTS is quite better than AC3.

NeroAAC suggests letting the profile setting to default which means the encoder will choose the best depending on the bitrate. Generally, HE profile is for low bitrates.

[tomcat_]

Normally, DTS is quite better than AC3.

NeroAAC suggests letting the profile setting to default which means the encoder will choose the best depending on the bitrate. Generally, HE profile is for low bitrates.

thanks for your prompt reply...

I have read the long debate between DTS and AC3 and how most of people tend to believe that DTS is of higher quality...so it looks like it makes a difference as an input as well?

If HE is for low bitrates i guess that LC will give better quality?

[nautilus7]

...DTS is of higher quality...so it looks like it makes a difference as an input as well?Yes it does.

If HE is for low bitrates i guess that LC will give better quality?I am not an expert on AAC, but i believe HE (high efficiency) uses some advanced features that are useful only if the bitrates are low. If you have enough bits (either you do a cbr or vbr or q encoding) these features are not needed, so LC (low complexity) is fine. You can read more about AAC on wiki, i think.

[tomcat_]

so i guess with DTS as input which has high bitrate AAC-LC would be fine?

[nautilus7]

DTS as input because it has higher quality. Depending on the bitrate you 'll give to your AAC file, you 'll choose the most appropriate profile. It doesn't have to do with source bitrate, but with output file bitrate.

I would go for AAC-LC @ q=0.5 using eac3to (if you don't know how to decode the dts track) and neroaacenc:

eac3to input.dts output.aac

[tomcat_]

thanks for the clarification...i didn't realize that the nero aac profiles was for the output bitrate...

i'm using megui for encoding the movie...so i guess it can still be done by putting as input dts and output NDAAC-LC-multichannel...

[tebasuna51]

Is only a suggestion but maybe...:
To transcode ac3 is enough -q 0.35
To transcode dts is enough -q 0.40
Greater quality than 0.4 (the default -q 0.5) is only needed for lossless sources.

I recommend you use quality methods instead fix bitrate (like MeGUI profiles) , then:

eac3to input.dts output.mp4 -quality=0.4

Or, if you use MeGUI, modify the profile to Variable Bitrate Q=0.4, AAC profile Automatic and uncheck the Increase Volume automatically (to avoid apply Dynamic Range Compresion)

[lexor]

Also a note, HE isn't supported well on standalones. So LC is a safer bet, you never know what you'll be doing with the track in the future.

[tomcat_]

ok...so from what i understand by reading around is that HE is getting better quality with more compression than LC...

also that DTS is better to be used as a source than ac3....

thanks all for your input...

[baudi]

I think not only the source is important but also the encoder.

Which is, in your opinion, the best DTS encoder?

I have realised that Surcode DTS encoder is not precise, fail with timestamp. i.e: before encoding ==> 1:36:19.840, after encoding ==> 1:36:28.453. Very imprecise encoder!

Thank you.

[lexor]

I think not only the source is important but also the encoder.

Which is, in your opinion, the best DTS encoder?

I have realised that Surcode DTS encoder is not precise, fail with timestamp. i.e: before encoding ==> 1:36:19.840, after encoding ==> 1:36:28.453. Very imprecise encoder!

Thank you.

You probably specified .dts as output. You can pass that through eac3to to remove zero padding. For future encodes, use .cpt output and then rename resulting file to .dts (.cpt is the type that DVDs and such use).

[baudi]

You probably specified .dts as output. You can pass that through eac3to to remove zero padding. For future encodes, use .cpt output and then rename resulting file to .dts (.cpt is the type that DVDs and such use).

Thank you for the info.