[botribun]

OpenELEC Frodo DEV Nightly Build
OpenELEC-RPi.arm-devel-20130903095520-r15502.tar.bz2 (93.6 MB)

OpenELEC Gotham DEV Nightly Build
OpenELEC_Gotham-RPi.arm-devel-20130903002518-r15502.tar.bz2 (94.1 MB)

These are just nightly builds, no extra stuff and so on like rbej's builds.

[doveman2]

Updated Frodo Branch

- [rbp/omxplayer] Add Dynamic Range Compresssion scheme

Aaargh, just when I thought I was settled on 3.1.7! Been waiting for DRC a long time: will try it out! (Also, I'm glad to see the pause-audio-sync issues have been addressed here!) Thanks! And thanks for still showing Frodo some love ;-)

Edit: Looks good! Had to set 'Volume Amplification' above zero to get volume control to work (DRC-related); and can confirm that sync issues are sorted! Nice!

Does this make Music the same volume as Movies as currently with Gotham I have to set Music to -30db, which makes it impractical to use XBMC for both Music and Movies as it takes about 60 presses of the volume keys to get from 0 to -30db? Does it also fix the bug where volume jumps to 0db when ffwding/rewinding music until a volume key is pressed?

[kreeturez]

Updated Frodo Branch

- [rbp/omxplayer] Add Dynamic Range Compresssion scheme

Aaargh, just when I thought I was settled on 3.1.7! Been waiting for DRC a long time: will try it out! (Also, I'm glad to see the pause-audio-sync issues have been addressed here!) Thanks! And thanks for still showing Frodo some love ;-)

Edit: Looks good! Had to set 'Volume Amplification' above zero to get volume control to work (DRC-related); and can confirm that sync issues are sorted! Nice!

Does this make Music the same volume as Movies as currently with Gotham I have to set Music to -30db, which makes it impractical to use XBMC for both Music and Movies as it takes about 60 presses of the volume keys to get from 0 to -30db?
Does it also fix the bug where volume jumps to 0db when ffwding/rewinding music until a volume key is pressed?

Not sure about music volume since I don't use music (though perhaps you could set an amplification figure for 'all' Music files to get the same default volume as videos?); but the issue with volume being reset after a FF/REW is sorted both in this build, and also in 3.1.7 official.

[doveman2]

Not sure about music volume since I don't use music (though perhaps you could set an amplification figure for 'all' Music files to get the same default volume as videos?); but the issue with volume being reset after a FF/REW is sorted both in this build, and also in 3.1.7 official.

That's some good news at least, thanks. I'm not sure how to set a negative (-30db) amplifcation figure for all Music, if anyone knows if this is possible please let me know how.

[popcornmix]

Does this make Music the same volume as Movies as currently with Gotham I have to set Music to -30db, which makes it impractical to use XBMC for both Music and Movies as it takes about 60 presses of the volume keys to get from 0 to -30db? Does it also fix the bug where volume jumps to 0db when ffwding/rewinding music until a volume key is pressed?

What amplification does is add an additional boost the volume, that will be removed if clipping would have occurred.

We'll assume that the music you have is encoded full range (we'll refer to that as 0dB), so sounds loud.
We'll assume the movies you have are encoded quietly (we'll refer to that as -30dB).

So, if you set amplification to 30dB, then the movies will be boosted to 0dB, and should sound fine (and loud). You will set your amplifier/TV volume to -30dB to compensate.
The music will be boosted to +30dB which would majorly clip/distort. The DRC scheme should kick in and attenuate the signal by 30dB to stop the clipping. You get 0dB comining out and it should sound similar to movies volume.

However if your music has quiet bits, then they won't clip, and will sound louder than normal. You'll probably be aware of volume increasing and decreasing.
30dB is really too high an amplification value. I believe with xbmc's default amplification scheme, they recommend limiting it to 12 or 15dB otherwise it becomes too noticable.

The scheme is really designed for an action film, than is typically -15dB, but has a gunfight and an explosion that hits 0dB briefly.
You can set the amplification to 15dB, and reduce your TV/receiver volume by the same amount. When the explosion occurs you don't wake up the neighbours.
(It saves you having to juggle the volume on the remote manually).

Currently it only works usefully when xbmc volume is on full as it relies on detecting clipping. You should adjust master volume at tv/receiver.
I think I can make it work with non-full volume.

I think I need to add a decay parameter which can be set to "infinite" for it to work better as a normalisation scheme (doveman2's request), rather than a DRC scheme.

[soupboy]

Just wondering if I'm doing something wrong with upgrading to Gotham versions? I'm copying KERNAL, SYSTEM and the MD5 files over to the update folder and rebooting from ssh.

Everything seems to go fine till it trys to update the System file and it will sit until eventually the screen goes black. Upon turning power on and off I get stuck at the Coloured bootscreen or sometimes it won't even boot.

I've also tried coping kernel and system to the sdcard and renaming kernel to kernel.img and still can't boot correctly.

System is running on USB with only SD to boot from. I'm downloading the new Frodo build and giving that a chance.

Seems im still doing something wrong with all the Gotham builds. Latest Frodo builds have updated and are running fine but Gotham no matter what I do gets stuck at the XBMC logo now. SSH starts and im able to connect and reboot, copy files across etc but for some reason it wont boot into the actual program.

Booting off usb of that makes any difference?

Thanks again for any help

[doveman2]

Thanks for the explanation popcornmix.

I'm currently using <ac3downmixgain>18.0</ac3downmixgain> to try and get the Movies/TV volume closer to my other equipment (PC and Xbox360), so that I don't have to adjust the TV volume drastically when switching between sources.

Movies generally sound OK although could probably do with a boost of the centre/dialogue channel on the downmix, even if the other channels have to be reduced to compensate. Maybe the DRC will help with this though, by allowing me to increase the gain without loud sections being too loud. Some movies are louder than others (generally stereo and probably badly encoded with too much gain) but most of them, particularly the quality multi-channel encodes are around the same level, so I don't think they've been encoded particuarly quietly.

I'm not sure that I do want a normalisation scheme, as I think that would ruin the dynamics in the music. What I think I need is just a user adjustable (i.e. in advancedsettings.xml) reduction (e.g. 30db) that applies to the music playback, to reduce it to around the same level as Movies/TV. I guess in theory ac3downmixgain could be used to instead boost movies to the same level as music but I guess it doesn't apply to stereo movies or TV, so that's not really going to work.

iPlayer has the same problem and is much louder than Movies/TV, so that needs a similar reduction amount, although I don't know if there's a mechanism to do this on a plugin level.

[popcornmix]

Thanks for the explanation popcornmix.

I'm currently using <ac3downmixgain>18.0</ac3downmixgain> to try and get the Movies/TV volume closer to my other equipment (PC and Xbox360), so that I don't have to adjust the TV volume drastically when switching between sources.

Movies generally sound OK although could probably do with a boost of the centre/dialogue channel on the downmix, even if the other channels have to be reduced to compensate. Maybe the DRC will help with this though, by allowing me to increase the gain without loud sections being too loud. Some movies are louder than others (generally stereo and probably badly encoded with too much gain) but most of them, particularly the quality multi-channel encodes are around the same level, so I don't think they've been encoded particuarly quietly.

I'm not sure that I do want a normalisation scheme, as I think that would ruin the dynamics in the music. What I think I need is just a user adjustable (i.e. in advancedsettings.xml) reduction (e.g. 30db) that applies to the music playback, to reduce it to around the same level as Movies/TV. I guess in theory ac3downmixgain could be used to instead boost movies to the same level as music but I guess it doesn't apply to stereo movies or TV, so that's not really going to work.

iPlayer has the same problem and is much louder than Movies/TV, so that needs a similar reduction amount, although I don't know if there's a mechanism to do this on a plugin level.

ac3downmixgain applies to all sources (stereo/music/multichannel). You should remove that setting and set amplification to 18dB. It should have the same effect but sound less bad if you were to clip.
Make sure you have "boost volume on downmix" enabled, or multichannel audio will sound much quieter.

Boost center channel is on my todo list.

I'm not going to add a boost music separately from video. That is too specific. A lot of videos normalise the audio (like iPlayer), so there's no guarantee that music is louder than video in general.

[doveman2]

ac3downmixgain applies to all sources (stereo/music/multichannel). You should remove that setting and set amplification to 18dB. It should have the same effect but sound less bad if you were to clip.
Make sure you have "boost volume on downmix" enabled, or multichannel audio will sound much quieter.

Boost center channel is on my todo list.

I'm not going to add a boost music separately from video. That is too specific. A lot of videos normalise the audio (like iPlayer), so there's no guarantee that music is louder than video in general.

ac3downmixgain seems a poorly named setting if it applies to all sources but hey

I do have "boost volume on downmix" enabled in System (although for some reason this option also appears in the pop-up menu in files view and shows it as disabled).

I tried amplification with the Frodo build instead of ac3downmixgain but that only boosts multi-channel movies, leaving my stereo movies far too quiet, so that's no good, even though it does leave Music and iPlayer at an acceptable volume. I couldn't check TV as that doesn't work for me with the Frodo build.

At least with ac3downmixgain all my Movies/TV are at acceptable volume, so I can use XBMC for Movies/TV but not Music or iPlayer but with amplification I can use it for Music and iPlayer but only some Movies.

If I've understood correctly, amplification acts as a basic compressor which might be OK for some people but others wouldn't want music and/or movies compressed and want to hear them as intended, so using amplification isn't a great solution to the problem anyway.

So what appears to be needed is a boost that only applies to movie files (and not streaming such as iPlayer, which is already loud enough, or if it's impossible to treat movies and streaming video separately as far as volume is concerned, a plugin-level volume control that can be used to reduce the volume for those plugins where it's necessary, to cancel the global boost) with DRC/normalisation being optional and switchable separately for movies and music so that those who want to use it for one or both can do so.

If something isn't done to properly balance the levels between Movies/TV, Music/iPlayer it simply makes it impossible to use XBMC for more than one of those without having to faff about increasing/decreasing the volume with numerous keypresses each time or risking damaging equipment/ears, so I'll have to just use it for Movies/TV for now.

[sneaker333]

Seems im still doing something wrong with all the Gotham builds. Latest Frodo builds have updated and are running fine but Gotham no matter what I do gets stuck at the XBMC logo now. SSH starts and im able to connect and reboot, copy files across etc but for some reason it wont boot into the actual program.

Booting off usb of that makes any difference?

Thanks again for any help

For the last few Gotham builds I randomly get 'stuck' at the XBMC logo, but if I ssh in and 'reboot' once or twice then it starts up fine. I haven't tried looking into it in any detail - maybe it's CEC related or something completely different. I was hoping it would fix itself in a newer build but it was still present in the 1st Sept build.

It seems there's something wrong that doesn't affect everyone and may be intermittent, which is why I was thinking of external influences like CEC.

[popcornmix]

If something isn't done to properly balance the levels between Movies/TV, Music/iPlayer it simply makes it impossible to use XBMC for more than one of those without having to faff about increasing/decreasing the volume with numerous keypresses each time or risking damaging equipment/ears, so I'll have to just use it for Movies/TV for now.

But what you are asking is impossible, which is why xbmc on any platform, or any other media player doesn't do it.
Support I had used get_iplayer to download an iplayer video, and then played it? Should that also be treated like iplayer and attenuated more than other videos?
Support I then remuxed it into an mkv file? Should i still spot it and attenuate it?
Suppose I rip a DVD and run a tool to normalise the volume, so it also is as loud as iplayer? Should that be attenuated more than other ripped files that haven't been normalised?

The only options are to parse and decode the audio for the whole file (which may take as long as playing the whole file) to find the maximum amplitude level.
Or to use a dynamic scheme, where the volume varies whilst it plays (it could be set with a very long release so it only adjusts each time it sees a new maximum, and will typically be stable after a few seconds).
Or you do what everyone else does, and juggle the volume if it seems too quiet or too loud.

[popcornmix]

ac3downmixgain seems a poorly named setting if it applies to all sources but hey

Yes, it was a hack using an existing advancedsetting (adding new ones has a lot of resistance)

I tried amplification with the Frodo build instead of ac3downmixgain but that only boosts multi-channel movies, leaving my stereo movies far too quiet, so that's no good, even though it does leave Music and iPlayer at an acceptable volume. I couldn't check TV as that doesn't work for me with the Frodo build.

It should apply to stereo and multichannel sources, but I think the current build only applies to multichannel. I'll fix that in next update.

[doveman2]

If something isn't done to properly balance the levels between Movies/TV, Music/iPlayer it simply makes it impossible to use XBMC for more than one of those without having to faff about increasing/decreasing the volume with numerous keypresses each time or risking damaging equipment/ears, so I'll have to just use it for Movies/TV for now.

But what you are asking is impossible, which is why xbmc on any platform, or any other media player doesn't do it.
Support I had used get_iplayer to download an iplayer video, and then played it? Should that also be treated like iplayer and attenuated more than other videos?
Support I then remuxed it into an mkv file? Should i still spot it and attenuate it?
Suppose I rip a DVD and run a tool to normalise the volume, so it also is as loud as iplayer? Should that be attenuated more than other ripped files that haven't been normalised?

The only options are to parse and decode the audio for the whole file (which may take as long as playing the whole file) to find the maximum amplitude level.
Or to use a dynamic scheme, where the volume varies whilst it plays (it could be set with a very long release so it only adjusts each time it sees a new maximum, and will typically be stable after a few seconds).
Or you do what everyone else does, and juggle the volume if it seems too quiet or too loud.

Course it's not impossible to balance Music and Movies/TV. If Movies/TV need to be boosted by 18db but Music doesn't, then you just need a boost that only applies to Movies/TV and not Music.

Sure, it might be impossible to identify a downloaded iPlayer video and treat it differently but that doesn't mean we shouldn't look at reducing the level when the plugin is streaming iPlayer so that it's about the same as everything else. Maybe people stream more than download from iPlayer, so doing this could make it much more usable for most people and those who do download are free to run the files through a program to reduce the volume.

Of course, if you mash up the volume on a DVD by normalising it, then it's going to be louder than other videos but we should be using the majority of properly encoded DVDs/Movies as our benchmark, not the odd one with ruined audio. I've got the odd video that appears to have been normalised and thus is quite a bit louder than the others, which is a pain but even then I think I only had to turn them down to around -10db and they were not as loud and overloading as when I played music.

You're focusing on worse case or problematic scenarios to suggest it's not worth trying to make the majority of sources work better, because you won't be able to achieve perfection as there'll always be some dodgy file that will still be too loud/quiet.

I can tell you that using Mediaportal, I can play TV, Movies or Music without having to worry about the volume blasting out (most of the time). It's using LAV to decode but I've got DRC and Mixdown disabled in that so I don't think that's doing anything to adjust the volumes (the Realtek control panel mixes down the multi-channel to Stereo but that doesn't do any volume processing either). iPlayer is louder still of course, because the source is normalised but I can use a profile in ffdshow to reduce volume (or normalise) flvs, which of course affects non-iPlayer flvs as well but I don't have any quality movies files as flvs and they only tend to be downloaded episodes of series, so normalising them isn't a big deal as they don't have great dynamic range to start with. It would of course be better to have the iPlayer plugin reduce the volume just for that.

For TV, I tend to use ffdshow (using a profile to affect only .ts files) as a post-processor to normalise and then reduce the volume, which helps prevent the large jumps in volume when the adverts come on (which the broadcasters always deny but everyone can hear) but it's not strictly necessary.

---

Yes, it was a hack using an existing advancedsetting (adding new ones has a lot of resistance)

Ah I see, yes there can be a lot of resistance to change in the XBMC community

It should apply to stereo and multichannel sources, but I think the current build only applies to multichannel. I'll fix that in next update.

Thanks, that would make it a lot more usable (for those who are happy to have the audio compressed of course)

[popcornmix]

Course it's not impossible to balance Music and Movies/TV. If Movies/TV need to be boosted by 18db but Music doesn't, then you just need a boost that only applies to Movies/TV and not Music.

The problem is that it's not just iPlayer. xbmc perhaps supports 1000 streaming sources.
Maybe 100 have normalised volume like iPlayer and should be played at -30dB.
Maybe 200 have fairly loud audio and should be played at -20dB.
Maybe 400 have normal volume and should be played at -10dB.
Maybe 300 have quiet volume and should be played at 0dB.

And some sites will have a collection of videos at different amplitude levels.
It's not just something I can create 3 rules that fit your current use cases and expect that to work for everyone.

Feel free to open a trac ticket or start a general xbmc request for per source volume settings.
It's not something I will support if it's not a part of core xbmc.

[zoltan]

Can I switch from Gotham to Frodo and then return to Gotham without problems?
Thanks