Bug in mp4 audio loader that produces audiable glitch

[Airal]

Note that the audio that is show when zoomed out some is actually heard. It is not a video issue. Seems to happen with mp4's but not wavs.

There is no glitch in the actual audio. Viewing in something like Adobe Audition doesn't show the glitch, nor is it heard. Seems to be a reaper issue. Works fine with VLC too.

This is a very consistent problem, happens on almost all mp4's. It seems wrap the tale end of the file to the start. Some type of offset bug

That is, if the file ends abruptly then part of that last 1/10 of a second gets wrapped to the start of playback. This means that audio that fades out to nothing before it ends won't have the issue. Hence, chop a mp4 up in the middle then import that and check.


Works fine with ffplay so this suggests a reaper issue or the reaper ffmpeg version. Probably a reaper issue.

[Airal]

Any news, feedback, anything? Surely this type of bug won't go unnoticed? It seems like a simple calculation bug(a sort of offset of 1 type of bug).

[Dstruct]

What happens if you use FFmpeg V3.3.1 from http://ffmpeg.zeranoe.com/builds/ ?

[Airal]

I don't know, I deleted all the ffmpeg stuff in the reaper dir and reloaded reaper and a project. It re-peaked everything and still had the same problem. What file exactly do I need to replace and where are they located? I'm using a portable installation.

[Dstruct]

You need the sharded build. Copy the DLL files to REAPER program directory.

[Airal]

Originally Posted by Dstruct

You need the sharded build. Copy the DLL files to REAPER program directory.

Ok, well, I removed everything in the reaper dir that related to ffmpeg along with all the stuff in the plugins dir. I uninstalled quicktime. I used procmon to check that reaper wasn't loading anything by ffmpeg(as far as I could tell). What it was doing is loading some stuff from vlc like libvlccore.dll, libavcodec.dll, libvlc.dll, etc..

I reloaded the project and the same problem.

I then renamed the vlc directory and reloaded the project. The mp4's were offline, so it looks like it was, at the very least, using vlc to load the mp4's.

I then readded ffmpeg and reloaded the project and the mp4's were back online. So it is using the ffmpeg now(played in the plugins dir).

BUT what I noticed throughout. Is that when I loaded the project for the very first time and hit playback, is that it wouldn't pop! (happened in the vlc case and even before that)

BUT after I played back the first time, it would always pop after. So, this is definitely some type of reaper bug. The pop changes too, sometimes it is brighter and sometimes bassy. It doesn't seem to happen when I first reload the project. It may happen with only certain types of mp4's or maybe an items setting issue.





vailable decoder information:

========== VLC ==========
VLC 2.0.x-2.2.x not found for correct architecture -- search path:
C:\Program Files\VLC

========== ffmpeg/libav ==========
ffmpeg/libav DLL decoder v57.99.100

Loaded from: C:\Reaper\Plugins\avcodec-57.dll
ffmpeg/libav configuration:
--disable-static
--enable-shared
--enable-gpl
--enable-version3
--enable-cuda
--enable-cuvid
--enable-d3d11va
--enable-dxva2
--enable-libmfx
--enable-nvenc
--enable-avisynth
--enable-bzlib
--enable-fontconfig
--enable-frei0r
--enable-gnutls
--enable-iconv
--enable-libass
--enable-libbluray
--enable-libbs2b
--enable-libcaca
--enable-libfreetype
--enable-libgme
--enable-libgsm
--enable-libilbc
--enable-libmodplug
--enable-libmp3lame
--enable-libopencore-amrnb
--enable-libopencore-amrwb
--enable-libopenh264
--enable-libopenjpeg
--enable-libopus
--enable-librtmp
--enable-libsnappy
--enable-libsoxr
--enable-libspeex
--enable-libtheora
--enable-libtwolame
--enable-libvidstab
--enable-libvo-amrwbenc
--enable-libvorbis
--enable-libvpx
--enable-libwavpack
--enable-libwebp
--enable-libx264
--enable-libx265
--enable-libxavs
--enable-libxvid
--enable-libzimg
--enable-lzma
--enable-zlib

ffmpeg/libav search path:
%PATH%
C:\Reaper
C:\Reaper\UserPlugins\64
C:\Reaper\UserPlugins
C:\Reaper\Plugins

========== DirectShow ==========
DirectShow available




Audio: 44100Hz 2ch 32bps
Audio: aac (HE-AAC) (mp4a / 0x6134706D), 44100 Hz, stereo, fltp, 66 kb/s


Ok, More news that might mean something:

I noticed that if I keep playing back over the start of the item, sometimes it doesn't pop, sometimes it's quite and sometimes it's loud.

If I stop the playback before any real audio starts, it eventually won't make a sound.

It seems like it could the item's buffer not being cleared. When there is sound that happens, it is retained in the buffer, when playback occurs again, it is not cleared. If the playback was loud, bright, or whatever, it will retain some of that in the pop.

For exmaple, if I just loop around the start of the item, but not allow any of the music to be in the loop(since the start of the item, musically, is quiet), there will never be any sound. But if I allow the end of the loop to cross in to music, then I will get pops.

And depending on what the end of that sound was, will shape the pop. (if it were loud at the end of the loop then the pop would be loud).

Also, the waveform will change depending on the end of the loop/

Here's a video, since I'm sure I wouldn't be believed otherwise:

http://www.filedropper.com/reaperglitch

Hopefully this can be fixed soon as I need to render some stuff and that glitch shows up in the rendering. Not only is there an aural glitch(I think just that the buffers need to be cleared after a loop when there is no item being played back), there is also a visual glitch(as I said, it tends to be the end of the item as if it were wrapped around).

I should also point out that I had a project with all mp4's in it and I saved it to a new dir and set the copy and change the format of items and it did not do so for all the items. Not sure why.

[Airal]

So, anyone gonna take a look at this?

[Dstruct]

Can you upload the affected file somewhere?

[Airal]

I tried to create a simple mp4 using the aac encoder I normally use but it didn't exhibit the problem. It turns out the mp4 files are a different encoding from what the aac encoder uses(or something changed

The files exhibiting the problem have the signature of

ftyp3gp6 3gp6isomndam

A file that has the problem. I manually cut the end of the file off to reduce the size, but it has the same effect(loads in my reaper so it should be ok).

https://files.fm/u/4t5wntgk

So, it does seem to be a bug with the specific encoding since I do not have these problems on other mp4's or mp3's.

[Airal]

So, it's been uploaded, anyone willing to try it?

[Dstruct]

Confirmed (5.40 x64 + FFmpeg 3.3.1).

[Airal]

Originally Posted by Dstruct

Confirmed (5.40 x64 + FFmpeg 3.3.1).

Woot! Thanks, Now maybe it will be taken seriously!

[Airal]

Will there be any work on getting this resolved or is it dead?

[bobobo]

i can reproduce it

it appears only at a certain zoom level .. approx. 1 bar an a little bit

and it can be heard the second time it is played.

[Airal]

Thanks bobobo, 3 pins down, I guess we'll have to get 7 more ;/

[Airal]

So, Is cockos gonna investigate?

[urednik]

Still here in Reaper 6.10

Waveform of certain (not all) MP4 files displayed incorrectly at smaller zoom level.
After clicking plus to enlarge at certain level it displays correctly.
Deleted waveform files, but no change.
Seems there is no option in preferences to delete cache or similar.