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Topic: Exhale CBR and low bitrate support (Read 2367 times) previous topic - next topic
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Exhale CBR and low bitrate support

Hello. As far as I know, Exhale doesn't support CBR or low bitrate encoding, so can support for these be added? (I think there should be no minimum bitrate - This is a seperate topic to make it easy to find.)

Re: Exhale CBR and low bitrate support

Reply #1 –
From: https://gitlab.com/ecodis/exhale

exhale currently makes use of all frequency-domain (FD) coding tools
in the scalefactor based MDCT processing path. Its objective is high
quality mono, stereo, and multichannel coding at medium and high bit
rates, so the lower-rate USAC coding tools (ACELP, TCX, Enhanced SBR
and MPEG Surround with Unified Stereo coding) won't be integrated.

Alternative encoder: https://www.poikosoft.com/music-converter

Re: Exhale CBR and low bitrate support

Reply #2 –
@celona I know that. I'm not asking for low-bitrate extensions, I'm asking for encoding low bitrates without these enhancements. The reason is that I want to hear how does USAC sound like in low bitrates and with CBR (low relative to the sampling rate). I also want these for an ABC/HR test (https://hydrogenaud.io/index.php/topic,127455 - the lowest SBRless >=32kHz option of Exhale can already be transparent to me). Plus, Exhale is currently the only practical way to get USAC encodings with low sampling rates.

Re: Exhale CBR and low bitrate support

Reply #3 –
Quote from: Klymins on
Hello. As far as I know, Exhale doesn't support CBR or low bitrate encoding, so can support for these be added?
No.

Chris
If I don't reply to your reply, it means I agree with you.

Re: Exhale CBR and low bitrate support

Reply #4 –
@C.R.Helmrich I understand that adding CBR support can require major changes, but adding support for lower bitrates (withOUT more low-bitrate extensions) definitely shouldn't, so can you consider adding several lower-quality VBR options at least? I want to hear the codec with unusably low bitrates too.

Re: Exhale CBR and low bitrate support

Reply #5 –
Quote from: Klymins on
Exhale is currently the only practical way to get USAC encodings with low sampling rates.

For Mac, GNU/Linux or BSD users like me Exhale is the only free encoder, but I think also for Windows users, who can buy the encoder for a small fee thanks to Poikosoft.

This does not mean we should be stubborn. In the past I tried Exhale at every mono/stereo combination for every bitrate and every sample, today the conversation has been removed.

The results were not consistent, then Exhale improved in five presets. In the meantime Opus, which I have always criticized (today I have to give a lot of satisfaction to Jean-Marc Valin and to those who have suffered my criticisms), has improved a lot and honestly if you do not want a paid MPEG-D USAC encoder, I recommend you try it, for speech only it is fantastic, you will get much better results than Exhale.

If instead you need to speak with a musical background that does not mask the voice, e.g. -32 LUFS for content normalized to -23 LUFS, as is done for broadcast in Europe, you will be better off using the paid xHE-AAC. Exhale It can be used at higher bitrates for all types of content, but at low bitrates it is no match. Think about it because if you thought the speech with Exhale at low bitrate was good, you will have to retrain your hearing (in the sense of recalibrating, training again) to pick up the artifacts, which are many.

From the command line:
Code: [Select]
opusenc --speech --bitrate 24 input.wav output.opus