AC3 Passthru when source is 2.0 or less

[j2k15]

Hi,

I use Handbrake to convert my DVD collection to Apple TV 3 and iDevice friendly files.

I use the ATV3 preset and then I use to keep 2 tracks for the audio :
- AAC Pro Logic II track
- AC3 Passthru

Since I have a 2.1 system and will later upgrade to a 5.1 system, this is the way to do when on the source DVD there is a AC3 5.1 track.

However, I've in my DVD collection old movies or TV Shows having only 2.0 or even 1.0.

My question is : does it worth to keep AC3 Passthru when source is AC3 2.0 or lower ?

[Baldrick]

I don't see why it would be worth to keep it.

Maybe if you shrink the aac track too much...or else should you not hear any audio quality loss.

[j2k15]

OK, so since I keep the default setting of 160kbps for the AAC track, it definitly does not worth to keep the AC3 tracks for tracks in stereo or lower.
I'll only keep AC3 Passthru for 5.1 then.
Thanks.

[hello_hello]

It might depend on the sort of 5.1ch system you buy and how you'll be playing the encodes.

Maybe Handbrake borrowed the "AC3 pass-through" description, as it's generally used to describe sending the un-decoded audio to a receiver or surround system for it's decoding pleasure, rather than the player itself decoding it. What is HDMI Pass-Through?

Pass-through would be mostly limited to various flavors of AC3 and maybe DTS, and the player can always decode the audio if need be, so for stereo AC3 it probably doesn't matter too much either way.... but still..... it might be something to consider.

[j2k15]

My current Sound System plays AAC Dolby Pro Logic II.
And also Dolby Digital.

So for DVDs with AC3 5.1 I'll keep :
- AAC Dolby Pro Logic II (AAC) (160 kbps)
- AC3 Passthru

For DVDs with 1.0 or 2.0 :
- AAC Dolby Pro Logic II (160 kbps)

Since there will be no real audible difference between AC3 2.0 and Dolby Pro Logic II. It might be overkill to keep both.

But again this applies only for TV Shows or movies having no AC3 5.1 audio track. If there is one, I use the AC3 Passthru feature to keep it.