What features would you like to see in opus-tools? Options

[NullC]

I'm looking for suggested features to get into opus-tools prior to the libopus 1.1 release.

Before I get 1001 suggestions for it: One frequently requested feature which was recently added is flac input in opusenc. I'm contemplating changing opusdec to use the new opusfile library— which would give it seeking and integrated http(s) streaming support. Also already on my todo list are default comment packet padding so updating metadata doesn't require rewriting the files and adding a replaygain tool.

Some people would really like it if opusenc/opusdec supported taking multiple input files e.g. opusenc *.flac but the implicit output file naming is pretty ununixy, and would break the interface and I got flamed all to heck last time I changed the opusenc interface.... so I'm not sure if/how I want to accommodate that usage.

What other things have you found missing?

[darkbyte]

I think a per channel bitrate setting would be useful. For eg. i'm encoding my music collection recently into 80kbps Opus and i have some mono chiptune albums and they are getting as high bitrate as 100kbps. If i manually encode them using --bitrate 40 kbps i still get very good quality but just a bitrate around 50-60kbps. So a --bitrate-per-channel 40 would be very useful. This will be 40kbps for mono, 80kbps for Stereo. Or maybe an option to provide a bitrate list for different channel configurations. Someone might want to give a mono recording a bit higher bitrate to be on the safe side.

This post has been edited by darkbyte: Mar 13 2013, 13:07

[jmvalin]

I think a per channel bitrate setting would be useful. For eg. i'm encoding my music collection recently into 80kbps Opus and i have some mono chiptune albums and they are getting as high bitrate as 100kbps. If i manually encode them using --bitrate 40 kbps i still get very good quality but just a bitrate around 50-60kbps. So a --bitrate-per-channel 40 would be very useful. This will be 40kbps for mono, 80kbps for Stereo. Or maybe an option to provide a bitrate list for different channel configurations. Someone might want to give a mono recording a bit higher bitrate to be on the safe side.

Actually, the 1.1-alpha encoder will automatically reduce the bit-rate when the input is mono (well, when the file has two identical channels).

[darkbyte]

Actually, the 1.1-alpha encoder will automatically reduce the bit-rate when the input is mono (well, when the file has two identical channels).

Strange, i'm using the 1.1-alpha-39-g10a35a5-babyeater build but i'm getting the described 100kbps bitrate on some chiptune samples instead of a lower one. Maybe the source is just sounds Mono to me but it has some differences because of dithering or such.

Btw, i forgot that with --bitrate 40 i'm using the --downmix-mono switch on a stereo source where both channels sound equal to me. Otherwise i get the described 100kbps bitrate. So either the mono detection of Opus doesn't work or my source files are just sound mono.
I think i'll upload a sample.

Mod: here's one 30sec sample
This seems like pure mono sample to me. If you encode it with --bitrate 80 it ends up as 71kbps. If i encode it with --bitrate 40 --downmix-mono it will be a 43kbps Opus and it sounds the same to me.
Looks like the beginning of this track is boosting the bitrate a lot. This track ends up at 100kbps but only if i encode it in it's whole length. This 30sec sample encodes into a close to 80kbps size. I think i can't upload the whole track here, it's from the commercial CD "C64 Orchestra - Run 10".

It would be interesting to see if the SID directly converted and upmixed into stereo WAV and then encoded with Opus will end up with the same high bitrate.

Mod2: okay i think i've screwed up something. Now i can't reproduce the high bitrate even on the whole length of the song. Maybe i was encoding yesterday with the non babyeater build.

I think you should ignore this post for now.

This post has been edited by darkbyte: Mar 13 2013, 18:12