Audio Codec Suggestions

General questions or discussion about HandBrake, Video and/or audio transcoding, trends etc.
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ddelella
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Joined: Sat Jul 06, 2013 4:12 pm

Audio Codec Suggestions

Post by ddelella »

So, I am looking to re-encode my x265 UHD movie collection. Since I want to keep the space small but still have a good picture I am targeting a video bitrate between 4000 and 4500 kbps. My main question is about the audio channels. I used to convert only the main audio track of the original video into AAC 96 Dolby Pro Logic II. I would like to keep the audio as high quality as possible but still keep the impact to overall file size minimal.

Scenario 1: AAC LC - 8 Channel @ X bitrate

I could convert the TrueHD audio of the original video to a set bitrate using the AAC codec. I tried it using 384kbps and the file size was around 4.36GB for a 2 hour movie.

Scenario 2: E-AC3 Passthrough

This is running now so I will have to wait to see the impact on the file

Scenario 3: TrueHD Passthrough

Keeping the original audio stream the file output was 7.91GB, nearly double the AAC. The audio tracks for TrueHD were several GB.

Is keeping it in TrueHD really worth it? If I have the Samsung HW-Q90R 7.1.4 Dolby Atmos system will I really be able to tell the difference between scenario 1 and 3? If you recommend I keep scenario 1 then at what bitrate should the AAC be encoded?

Help!

musicvid
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Re: Audio Codec Suggestions

Post by musicvid »

You can't "pass through" audio formats that are not in the original streams. They will be re-encoded.
So if your main audio is TrueHD, you would be passing it or re-encoding to AAC or another codec.
But we can't know for sure, because the required encode logs were unfortunately not included with your support request.

ddelella
Posts: 5
Joined: Sat Jul 06, 2013 4:12 pm

Re: Audio Codec Suggestions

Post by ddelella »

This was not a support request. It was a community feedback post. I am unsure which is the best method to handle the issue and I do not know much about Dolby Atmos TrueHD to know if there is noticeable differences between TrueHD and AAC 640kbps 8-channel. I understand lossy vs uncompressed will never be the same but can the normal person tell the difference with a 7.1.4 soundbar? Is a soundbar with upward firing even worth getting if I don't keep the TrueHD?

I can confirm you were correct. The EAC3 just output 8-channel AAC again.

So my options are (rough estimates):
8-channel AAC 640kbps = 4.8GB
TrueHD Passthrough = 8.2GB

What would be your pick and why?

Woodstock
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Re: Audio Codec Suggestions

Post by Woodstock »

When you're asking for specific suggestions on what to change to achieve certain results, that pretty much defines a "support request", not to mention it is VERY difficult to suggest a change without knowing what was done before, and why it wasn't acceptable.

Generally speaking, dropping the idea of "lossless compression" will reduce the size of audio tracks, because most codecs involve compressing the audio in a lossy fashion, then adding in the information to make up for the lossy audio. MakeMKV, when reading a TrueHD track, for example, can extract the base AC3 audio and put it in the MKV file as a separate track. It can do the same for DTS-HD MA audio, extracting the original (lossy) DTS track.
but can the normal person tell the difference with a 7.1.4 soundbar?
In general, a "normal person" cannot tell the difference between lossy and lossless audio playback, unless the differences are exaggerated. It's primarily marketing; by the time you add physical speakers to the equation, the difference is cancelled out... Except on an oscilloscope.

mduell
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Re: Audio Codec Suggestions

Post by mduell »

ddelella wrote:
Mon Feb 24, 2020 2:01 am
So, I am looking to re-encode my x265 UHD movie collection. Since I want to keep the space small but still have a good picture I am targeting a video bitrate between 4000 and 4500 kbps.
These two statements are in stark contrast to one another, since 4Mbps is overkill for some movies and not nearly enough to get a good picture for others.

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