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1
Opus / Re: Can anyone reliably ABX OPUS at 160kbps?
Last post by jmvalin -
Opus has CVBR mode which is an equivalent to Apple AAC ABR.
Actually, as surprising as it may sound, Opus' CVBR is actually equivalent to what AAC encoders call CBR! That's because MPEG codec CBR modes use a bit reservoir where each frame is allowed to vary in bitrate so long as the cumulative deviation never exceeds the equivalent bits for one frame. Turns out that the Opus "constraint" in CVBR does exactly that. It's just that the bit packing is done more cleanly, without a bit reservoir. What Opus calls CBR (or sometimes hard CBR) is real CBR, with each frame being exactly the same size. That is something most MPEG codecs cannot do reliably without wasting bits.
2
Opus / Re: Vorbis Sounds better than Opus at 192 kbps.
Last post by lithopsian -
Might be worth the OP explaining just how the tracks being compared were generated.  Any easy-to-identify widespread differences between modern codecs at 192 kbps are more likely due to mistakes in encoding or playback than inherent in the codec itself.
3
Opus / Re: Vorbis Sounds better than Opus at 192 kbps.
Last post by lithopsian -
My experience is that Opus suffers from very occasional killer samples (or occasional incidents in longer tracks if you have the patience to listen for them) that don't completely resolve with higher bitrates.  Some of these have been fixed as outright bugs, but some remain.  Vorbis is generally worse than Opus at a given (relatively low) bitrate, as shown in multiple listening tests, but also more consistent in improving at higher bitrates.  I haven't found any Vorbis killer samples that don't just fade away for my ears by about 192 kbps.
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General A/V / Re: Why does LAME cut off frequencies differently for CBR and VBR ?
Last post by Porcus -
V0 has lower bitrate than 320. As 320 is max, "variable" would have to mean less.

Think of CBR as "Here is a number n and a task T. Hire the n best people to do T!" and VBR as "Here is a task T. Hire the N best people for the task T, where you choose N high if necessary for the task in question, and low if not!".

Evidently, VBR requires more smartness, as you outsource to it to determine N as well. If you feed a VBR encoder a signal with a sine tone at full volume over some ambient noise at -90 dB, it should choose to produce a small file. If you feed a CBR encoder the same thing, it will use the "n" you told it to.

But then you cannot compare V0 and CBR 320.  You should compare V0 with CBR at, kinda, "what would you expect to be enough?".
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