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Topic: Opus bitrates for 2.0CH & 5.1CH & 7.1CH audio (Read 1831 times) previous topic - next topic
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Opus bitrates for 2.0CH & 5.1CH & 7.1CH audio

just want clarification regarding the various used bitrates for Opus codec as it's considered efficient in audio compression with minimal quality loss in lower bitrates.

Presently, I'm using 384Kbps (64Kb per channel per sec) for 5.1CH in VBR setting and 448Kbps (64Kb pr channel per sec) for 7.1CH in VBR setting. and 128kbps (64kb pr channel per sec) For 2.0 CH In VBR Setting. Are these bitrates worth (not needlessly high) or lower bitrates in opus are also considerably efficient? For Movies And Anime Tv Shows Etc.

Re: Opus bitrates for 2.0CH & 5.1CH & 7.1CH audio

Reply #1 –
Only you can ABX what sounds good to you. Based on ABX tests I've seen here, I chose 96kb per channel for safety. It is still more space savings over MP3, so I am happy with it.

Re: Opus bitrates for 2.0CH & 5.1CH & 7.1CH audio

Reply #2 –
try opus vbr 288kbps for 2ch. its awsome quality
In metal high tones that can not even hear can be important for feeling. tones from other side. the dark side. use the bits Luke

Re: Opus bitrates for 2.0CH & 5.1CH & 7.1CH audio

Reply #3 –
Quote from: 123jippo on
try opus vbr 288kbps for 2ch. its awsome quality

Why? Unless there is data to support that my current settings are inadequate then it's just wasted bits.

Re: Opus bitrates for 2.0CH & 5.1CH & 7.1CH audio

Reply #4 –
Hello J-Culture.

There is nothing wrong with your bitrates, but I think we should talk about one other thing - compatibility.

I assume you are using H264/H265 in MP4/MKV container.
Opus is mostly used with VP9/AV1 in WebM container.

So if you are using MP4/MKV I think you should switch to AAC-LC for 2.0 and AC-3 for 5.1.

AAC-LC is transparent at 192 kbit/s for music - tested by qualified listeners in controlled environment.
For average person, it will be transparent at even lower bitrate. I bet 99% of people can't tell the difference between 128 kbit/s and lossless.
I personally use Apple (qaac) encoder at 160 kbit/s with --no-delay switch to ensure audio/video synchronization.

When it comes to 5.1, I think you should use AC-3, also known as Dolby Digital.
5.1 became popular when DVDs started coming out, and AC-3 was mandatory format so it will have highest compatibility.
Even my decade old plasma TV will output AC-3 using Toslink and VLC can play it just fine on Android.
You can use 448 kbit/s if you want to save some space or you can use 640 kbit/s if you want to go "all-in".

What about 7.1?
Let's be honest, if somebody has 7.1 audio system, he definitely wants original uncompressed audio.
You can use E-AC-3 (Dolby Digital Plus) if you really want but I just don't see a point in it.

Why I can't use AAC-LC for 5.1?
You can use it, but you can't bitstream it. Audio will always be decompressed to pure PCM and you will need some very expensive equipment to use it.
Most of the time it will output stereo only because of certain limitations. (I won't go into details, too much to write...)
gold plated toslink fan

Re: Opus bitrates for 2.0CH & 5.1CH & 7.1CH audio

Reply #5 –
Quote from: 123jippo on
try opus vbr 288kbps for 2ch. its awsome quality
Watch it!

Besides, platitudes or water cooler talk have never contributed  to any discussion or made anyone's point come across, have they really?
• The older, the lossier
• Listen to the music, not the media it's on.
 

Re: Opus bitrates for 2.0CH & 5.1CH & 7.1CH audio

Reply #6 –
Quote from: Markuza97 on
Hello J-Culture.

There is nothing wrong with your bitrates, but I think we should talk about one other thing - compatibility.

I assume you are using H264/H265 in MP4/MKV container.
Opus is mostly used with VP9/AV1 in WebM container.

So if you are using MP4/MKV I think you should switch to AAC-LC for 2.0 and AC-3 for 5.1.

AAC-LC is transparent at 192 kbit/s for music - tested by qualified listeners in controlled environment.
For average person, it will be transparent at even lower bitrate. I bet 99% of people can't tell the difference between 128 kbit/s and lossless.
I personally use Apple (qaac) encoder at 160 kbit/s with --no-delay switch to ensure audio/video synchronization.

When it comes to 5.1, I think you should use AC-3, also known as Dolby Digital.
5.1 became popular when DVDs started coming out, and AC-3 was mandatory format so it will have highest compatibility.
Even my decade old plasma TV will output AC-3 using Toslink and VLC can play it just fine on Android.
You can use 448 kbit/s if you want to save some space or you can use 640 kbit/s if you want to go "all-in".

What about 7.1?
Let's be honest, if somebody has 7.1 audio system, he definitely wants original uncompressed audio.
You can use E-AC-3 (Dolby Digital Plus) if you really want but I just don't see a point in it.

Why I can't use AAC-LC for 5.1?
You can use it, but you can't bitstream it. Audio will always be decompressed to pure PCM and you will need some very expensive equipment to use it.
Most of the time it will output stereo only because of certain limitations. (I won't go into details, too much to write...)

I think your argument on format selection for compatibility is very valid, especially when it comes to movies as the likelihood of using a home theater decoder in that scenario. Is there some issue with using OPUS in a MKV container?

Re: Opus bitrates for 2.0CH & 5.1CH & 7.1CH audio

Reply #7 –
Quote from: DrivingVertigo on
Is there some issue with using OPUS in a MKV container?
No, there are no issues. I'm using Opus for all my encodes (x265, FHD, UHD, SDR, HDR, DV) in a MKV container. No problems using MPC-HC / VLC for playback on the PC, also fine on my Kodi-Box. Opus will decoded to PCM and send via HDMI to the AVR, as the AVR can't decode OPUS, the same applies to AAC.

If you need compatibility with a lot of devices, I would advice you to use AC3.