Ok, as NullC suggested I've played a bit around with the CBR mode of Opus (last exp version) and found an even better example at which the VBR mode may exaggerates a bit.
Audio Link
At a target bitrate of 192 kbps Opus is giving this sample an average of 214 kbps while it's not even ABXable for me at 96 kbps CBR. Other encoders behave different by giving it only around 150-160 (Lame and Ogg) or even just around 100 kbps (FhG AAC).
Bitrate is only part of story. It's always worthy to check if LAME, Aotuv or FhG decrease bitrate without any audible issues.
My results for this sample:
ABC/HR for Java, Version 0.53a, 11 August 2012
Testname:
Tester: IgorC
1L = D:\Samples\01_Kick_sample\FhG VBR 5 192 kbps.wav
2L = D:\Samples\01_Kick_sample\48kHz_192kbps_Opus(transients build)_44.1kHz_SoX.wav
3L = D:\Samples\01_Kick_sample\AoTuV VBR q6 192 kbps .wav
4R = D:\Samples\01_Kick_sample\LAME 3.99.5 V2.wav
Ratings on a scale from 1.0 to 5.0
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General Comments:
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1L File: D:\Samples\01_Kick_sample\FhG VBR 5 192 kbps.wav
1L Rating: 4.9
1L Comment:
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2L File: D:\Samples\01_Kick_sample\48kHz_192kbps_Opus(transients build)_44.1kHz_SoX.wav
2L Rating: 4.8
2L Comment:
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3L File: D:\Samples\01_Kick_sample\AoTuV VBR q6 192 kbps .wav
3L Rating: 4.4
3L Comment: muddy bass. Probably as well as some tine pre-echo
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4R File: D:\Samples\01_Kick_sample\LAME 3.99.5 V2.wav
4R Rating: 3.5
4R Comment: pre/post echo.
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ABX Results:
Even such mature codecs like Vorbis and LAME drop bitrate but aslo drop quality. While only FhG AAC (VBR 5 192 kbps) could drop bitrate down to 120 kbps without any audible issues. I'm not sure how it will be easy or difficult to do that for Opus.
Ok, as NullC suggested I've played a bit around with the CBR mode of Opus (last exp version) and found an even better example at which the VBR mode may exaggerates a bit.
Audio Link
At a target bitrate of 192 kbps Opus is giving this sample an average of 214 kbps while it's not even ABXable for me at 96 kbps CBR. Other encoders behave different by giving it only around 150-160 (Lame and Ogg) or even just around 100 kbps (FhG AAC).
Agree, CBR 96 kbps was already very good.
It's great sample where Opus could save bitrate. All encoders decrease the bitrate on this sample without any audible issue. FhG AAC (VBR 5 ~192 kbps) shines again, 105 kbps while keeping perfect quality.
Ok, here is one more sample that seems to make problems (with the 1.01 release candidate).
Bombat Sample
There is this sharp sound of some kind of distorted voice on which the encoder introduces noise/distortions. It's especially obvious at 64 kbps, but also noticeable at higher bitrates up to 160 kbps.
It's rather a killer sample itself than a particular issue for 1.0.1. I couldn't find any other lossy codec that makes any better for this sample.
Comparison with HE-AAC:
ABC/HR for Java, Version 0.53a, 11 August 2012
Testname:
Tester: IgorC
1L = D:\Samples\HA_opus_topic\03 Bombat\Opus_EXP7_Transients_64kbps_resampled_44.1kHz_SoX.wav
2L = D:\Samples\HA_opus_topic\03 Bombat\Opus_1.0.1_64kpbs_resampled_44.1kHz_SoX.wav
3R = D:\Samples\HA_opus_topic\03 Bombat\FHG_VBR3_64kbps.wav
Ratings on a scale from 1.0 to 5.0
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General Comments:
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1L File: D:\Samples\HA_opus_topic\03 Bombat\Opus_EXP7_Transients_64kbps_resampled_44.1kHz_SoX.wav
1L Rating: 3.8
1L Comment:
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2L File: D:\Samples\HA_opus_topic\03 Bombat\Opus_1.0.1_64kpbs_resampled_44.1kHz_SoX.wav
2L Rating: 3.8
2L Comment:
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3R File: D:\Samples\HA_opus_topic\03 Bombat\FHG_VBR3_64kbps.wav
3R Rating: 3.4
3R Comment:
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ABX Results: