Weird, does CVBR do the same?
Did you use some low-pass with the C64 stuff? I know I tried some emulator once and it was producing way too much harmonics above 12kHz, it was practically unlistenable using monitoring headphones (unless you like your ears bleeding from the treble).
Are you talking about a one-channel file or a two-channel file where both channels are the same. If it's the former, then the behaviour is probably normal considering that your C64 music is likely highly tonal.
The SID synthesizer is rather simple, the spectrum of frequencies probably very distinct. Similar to the results for "Stranglehold".
There is a new opus 1.0.1 RC3 release candidate up, as well as a 0.1.5 opus-tools at http://www.opus-codec.org/downloads/ . These releases make minor build system changes and other small cleanups, other than some command-line options being changed a bit in opus-tools they are functionally identical to prior versions.As always testing and trouble reports are appreciated.
Why "--music" option was removed?
If a tool modifies the OpusHead "output gain" field, it MUST also update or remove the R128_TRACK_GAIN comment field. There is no comment field corresponding to Replaygain's ALBUM_GAIN; that information should instead be stored in the OpusHead 'output gain' field. To avoid confusion with multiple normalization schemes, an OpusTags packet SHOULD NOT contain any of the REPLAYGAIN_TRACK_GAIN, REPLAYGAIN_TRACK_PEAK, REPLAYGAIN_ALBUM_GAIN, or REPLAYGAIN_ALBUM_PEAK fields.
Chiptunes and similarly synthesized music seem to pose a problem for Opus. I've encountered a difficult sample for Opus 1.0.1 RC3: The beginning of the track "Flicker" by Big Giant Circles, which consists of two side-alternating NES-like synths.
Please be sure to also try the exp encoder higher up in the thread here.
Setting 1.0.1RC3 T1 T2VBR 64 66 130 118VBR 100 103 191 182VBR 130 134 239 233VBR 200 206 348 346
Actually, we're looking into adding it. Most probably will be in the next intermediate build.Thanks!
Chiptunes and similarly synthesized music seem to pose a problem for Opus. I've encountered a difficult sample for Opus 1.0.1 RC3: The beginning of the track "Flicker" by Big Giant Circles, which consists of two side-alternating NES-like synths.Opus produces a distortion that is quite annoying up to VBR ~130 kbit/s and can be ABXed up to VBR ~200 kbit/s. The distortion is most noticeable in the first 5-6 seconds, after which an underlying pad sound begins to make distinction a little more difficult. I also did a test with VBR ~300 kbit/s but could not get conclusive ABX results.I've uploaded the sample FLAC, the encoded Opus files and the ABX results for 130, 160 and 200 kbit/s VBR here so you can have a look (and a listen) at it. I don't have access to my FTP from the office, so Dropbox will have to do.Download Sample ZIP
I've tested the two exp encoders from #365 and got results similar to those of darkbyte's SID music: With both encoders, bitrates were way higher than with 1.0.1 RC3.
For the sample I've tested, the other lossy encoders don't show the same behaviour. I did a quick comparison at ~64 kbit settings, and while LAME V9 goes up to an average of 80 kbit/s, the other encoders (Quicktime AAC, Nero AAC, aoTuV Vorbis, Opus 1.0.1RC3) all stay around 64 kbit/s. Plus, the two AAC encoders produce less noise than the two Opus encoders which use roundabout the double amount of bits.Of course I know this is difficult terrain for lossy codecs, where distortion and noise can quite easily be found amidst the clean synth waves. Nevertheless, at this point this seems to be not only problematic in comparison to other kinds of sound, but also in comparison to other encoders.
I'm not sure what "VBR 130 (exp)" means because you have datapoints where 130 was delivered and where it was requested. ABXable for 66kbit/sec collection average (requested) is expected, hopefully it just doesn't sound bad. ABXable for 130 collection-rate (requested) would be worth a closer look.
ABXable for 130 collection-rate (requested) would be worth a closer look.
Anybody knows what Opus Encoder setting gives "same" result as Ogg Vorbis at q6.0?
I'm just wondering about the implications of this for people using OPUS as a music storage format (rather than streaming).While I'm entirely happy to normalize all my music using Album Gain, I know there are people who are a bit 'precious' about preserving of being able to revert to the 'original loudness' of the tracks as if it were 'intended' by a mastering engineer with reference to a standard, which is barely ever the case, unlike with calibrated movie theatre audio.
Current (dev) builds of rockbox now have preliminary support for Opus. The current code has zero optimizations, so older devices probably won't be able to play it without skipping, but thats normal for new codecs before they get rewritten for ARM
Quote from: saratoga on 21 September, 2012, 11:07:43 AMCurrent (dev) builds of rockbox now have preliminary support for Opus. The current code has zero optimizations, so older devices probably won't be able to play it without skipping, but thats normal for new codecs before they get rewritten for ARM Not sure whether there is much sense to keep development for old devices. DAPs start to see their end while the sales of smartphones grow. Today the vast majority of smartphones have powerful CPUs.Have tried Opus on phone with Android http://rasher.dk/rockbox/android/ . Works well and has plenty of battery life. Probably the battery life isn't an issue anymore. Anyway people should recharge it (almost) every day.