VGM playback problems

[Corvus Lusor]

Hello all !
First of all, thank you for creating such a wonderful piece of software. Having some problems with my computer and chiptune playback, I can at last listen to some of my favorite tunes again.

Now the serious part. I noticed some problems with VGM/VGZ files. As far as I know, they haven't been notified on this forum yet, thus here am I to do it.

First problem: it seems that RB displays 2:30 as track length, whatever the duration actually is.
Second problem: RB correctly reads the track length (although not displaying it correctly, as said above), but fhe fadeout ends instead of beginning at that time. On long tracks, it's not too much a big deal, but on non-looping tracks, the track can't be fully heard. It seems to be in fact to problems in one:  early fadeout for looping files and fadeout even on non-looping files.
Third problem: unless I'm mistaken, the codec is outdated. The specification of the format evolved in order to support new chips, replacing de facto formats such as NSF or HES and supporting previously totally unsupported chips. Playing such files currently only outputs silence. It wouldn't hurt to update it in order to be fully compatible, although it may require quite some work.

Thank you for your feedback.

[LambdaCalculus]

I don't understand very much of what you're saying at all. You'll need to clarify on your points.

Now, as far as the VGM codec is concerned, the only thing that really rings true is that you'll need a relatively powerful device to be able to smoothly
play VGM files. Your mileage may vary, but I've had luck with the Gigabeat F, AMS Sansas, iPod Classic, and Android versions in terms of smooth
playback.

Second, what files are you playing that are giving you issues? Are you using an older set of VGM files that are perhaps incorrectly tagged? Have you tried
several different VGM files? What happens if you play the files on another player?

The screenshot below was taken with a UI simulator, and should illustrate that VGM playback is working just fine from my tests.

Lastly, I don't see what NSF and HES have to do with this, as these are completely separate codecs and have nothing to do with each other, other than the
fact that they are chiptune formats. NSF is only for NES/Famicom chiptunes, while HES is only for TurboGrafx-16/PC Engine chiptunes.

[Corvus Lusor]

Sorry for not being clear. Here's an (i hope so) better explanation with my answer to your remarks.

For information, my player is a Sansa Clip Zip, and I have the latest version (3.13) of Rockbox. Yes, I tried several files, FM and PSG, with the same result.

The sound itself if, as far as I can tell, perfect for Sega Master System soundtracks, encoded in VGZ. Nothing to say about it. On your screenshot, the displayed duration seems correct indeed. My files are from smspower.org, and I do hope they are correctly tagged as they are a main VGM files source, and they are usually reviewed by an administrator (usually Maxim, who developed part of the VGM format) before being put online. And I don't really have the possibility to try with another player (maybe can I try with my office PC with Windows+Winamp, but lol)

If the displayed duration on my player is wrong, the music plays for the right time, except that, as I said, the codec begins the fadeout before the end of the loop instead of beginning it after the loop. If I'm still unclear:

Current behaviour:

Code: [Select]

<               volume = 100%              ><fadeout>(end)
{start}{main part, first play}{main part second play}

Excepted behaviour, if I'm not mistaken:

Code: [Select]

<                    volume = 100%                  ><fadeout>(end)
{start}{main part, first play}{main part second play}{main part third play}

As I said, it's not really a big problem. A bigger problem is that non-looping musics are affected by the fadeout too:

Current behaviour:

Code: [Select]

<volume = 100% ><fadeout>(end)
{           song        }

Excepted behaviour:

Code: [Select]

<volume = 100%>(end)
{     song    }

The result is that I can't hear the end of the tracks.

What I can't explain is that I experience these problems while everything seem to be OK for you.

As for NSF and HES, I was simply stating that these formats may in the future become obsolete as they will be replaced by VGM, the specification of which evolved in order to support the corresponding chips. Now, there are VGM files of Famicom or PC Engine music, but they are not yet supported by the current version of Rockbox, which only outputs silence for these. The same goes of course for other chips I didn't mention for the sake of simplicity, I just opted for common formats/chips.

If I may add something, I tried the soundtrack of Phantasy Star IV, and the sound was polluted by an enormous buzz. I then tried to update my VGM files, thinking they could be obsolete. Hurray, the sound was clear after that! The next time, the buzzing sound was here again. Now I try again, and the sound is clear. For now, I only tried with this soundtrack. It's not a battery problem, because each time it was fully charged. As far as I know, there is no noticeable usage difference between these tries, there does not seem to be any logic behind this, it just seems random. I'll make other tries in order to understand, but I have little hope to lighten the problem.

[[Saint]]

Two things,

1: - The Rockbox version you're using is absolutely ancient, and you should update it. For the targets with stable releases there really is absolutely no reason to avoid using the development builds, and in fact, they are almost certainly more stable than the "stable" releases due to the fact that they contain an extra thirty months or so worth of active development.

Some users seem to want to avoid the development builds for some reason, but it is worth pointing out that if that reason is due to perceived risk or the assumption of loss of stability, that the development builds have received some two and a half years of active development in the way of added functionality, bug fixes, stability improvements, efficiency improvements, etc., etc., and so on... Essentially making them more stable than the "stable" releases.

2: - VGM is a hilariously inefficient format, you should probably transcode these files to something more sane, like mp3 (perhaps in a variable bitrate if space is a concern), opus, vorbis, etc., etc., and so on...

The takeaway from that statement being just because we /can/ play a particular codec doesn't mean its a good idea to. See, for instance, APE.


[Saint]

[Corvus Lusor]

I get the point. I usually stick to the relase version of softwares because even with the release versions, I don't know how it can be, there is always something wrong with the features I often use. Needless to say that in that case a dev version would be worse. But if you say it's fine with Rockbox, I'll try, thank you for the piece of advice.

As for the unefficiency of the VGM format, I can't tell and won't even try to analyze the format to do so. Well, yes, I may convert them into other formats, but the sound will not improve, the filesize will dramatically increase, I will have to keep two versions of each track (as I won't delete the source files), and it will be painstaking to convert each track I want to listen. You may say it's the same with CDs and you'll be right, but I can't put a CD in my player, while Rockbox allows me to use VGM files. Why should I turn down a feature for which I knowingly chose my player? I chose a Sansa Clip Zip with Rockbox just because this combination makes things much easier with video game musics. Rockbox still lacks support of PSF files and I try to cope with that, but it's rather boring, as boring as it was with SPC or VGM files.

Edit: I updated to the last available version. Result:
-The 2:30 display is still here for any of my VGM files (which are from three distinct sources).
-The fadeout is now correct (whew!)
-The codec only supports an older version of VGM.

By the way, I noticed some tracks end abruptly, with no apparent reason. For example The End of the Millenium, from the Phantasy Star IV soundtrack. I tried with the simulator and with Audio Overload, with no problem, so it seems that the problem occurs only with the hardware. Is it a memory problem? So, why do other similar tracks work? Until now, the problem didn't occur with SMS tunes, only this soundtrack.

[saratoga]

This might be interesting:
http://www.rockbox.org/tracker/task/12176

[Corvus Lusor]

Update: I found the answer for some of the problems. I decompressed my VGZ files to VGM, and the real duration is now displayed (as well as the metadata, by the way). The tracks don't seem to stop abruptly anymore, which confirms the memory problem. Rockbox can't access all the VGM content of the VGZ files if it's too big for the player and it can't read any of the metadata nor duration if the format is VGZ. Things are more clear like that.

So, it means that the simulator doesn't have the real thing's memory limitation, as I couldn't reproduce the problem with it.

[404_user_not_found]

Well, yes, I may convert them into other formats, but the sound will not improve,

Rockbox can incorrectly decode some chiptunes. So it's a not a bad idea to convert chiptune to famous format. Some windows specific decoders of chiptunes have a quality improvements like SINC interpolation in SPC, or stereo effect in NSF. Also you can just buy a sd card with huge capacity.

Rockbox still lacks support of PSF files and I try to cope with that,

This is a high consume format, so it is a not a good idea to play this format in weak player

[[Saint]]

So, it means that the simulator doesn't have the real thing's memory limitation, as I couldn't reproduce the problem with it.

That would be quite correct, which is why its a simulator, and not an emulator.


[Saint]

[Corvus Lusor]

So it's a not a bad idea to convert chiptune to famous format.

I agree. But we're far from a drag and drop of files, not very convenient, especially when it comes to rare file types.

Indeed, an emulator would be *a little* more difficult to develop.

[saratoga]

If anyone is interested, I am all for improving our decoder. Emulated formats tend to be very hard to fully support though.

[Corvus Lusor]

Of course, I'm interested.

I tried the vgm playing capabilities and found some problems. For example, I took the FM soundtrack of Ys on the Master System. What I found is that drums sound broken: on at least some of the tracks where only the bass drum can be heard, the remaining has vanished, so the pretty rhythmed tracks sound cheesy. When I convert into wav using ValleyBell's tool, the sound is correct, so the problem isn't with the vgm file.

Another problem: in a previous post, I talked about some buzzing sound. I managed to reproduce the issue to some extent. Here's exactly what I do: I start playing the "Palace" track from the same soundtrack then switch off my player. Next, I switch it on and choose the option "resume playing" (or so). The track sounds fine at the beginning, but when it comes to the clarinet, its sound just makes my ears bleed.