Avidemux Forum

Issue with playing mp4 (x264) variable frame rate (~60fps) in Avidemux.
- The time display stops updating
- (not responding) briefly displays in the window title
- controls are sometimes not responsive.
- display micro-freezes.
The issue will typically occur within 10s of pressing play.
I'm using dxva2 on Win10 with Avidemux v2.7.8 Vc++/2.7.9 win64.
- v2.7.1 seems to work better (frame flashes green when you press play).

Occurs on the testfile from this thread: https://avidemux.org/smif/index.php?msg=90928
but also occurs on lower bitrate videos from various sources (incl. 480p60).

EDIT2: also occurs with constant frame rate
- the issue persists after recompressing to Constant Frame Rate with ffmpeg.
- the issue is also present with 60fps youtube videos (tagged Constant Frame Rate)

GUI becoming unresponsive when FPS matches the refresh rate of the display is a known issue.

- setting the monitor to 50Hz solved the problem for 60fps videos (and caused the same issue for 50fps content).
- setting the monitor to 59Hz did not solve the issue.

This is a serious issue if it affects all 59-60fps content on 60Hz monitors.

Quote from: butterw on April 07, 2021, 03:52:46 PMThis is a serious issue if it affects all 59-60fps content on 60Hz monitors.

Yes, sure it is. I wish a had an idea how to fix this.

With some video it makes Avidemux very frustrating to use. I'm assuming this isn't a Windows only problem. 
v2.7.1 seems to work, when did this start ?

Unrelated: is it possible to recompress variable frame rate x264 to constant frame rate (ex: 59.94fps) with Avidemux ?

I have no problem with software decoding (4k 60fps is OK)

Quote from: butterw on April 07, 2021, 06:35:15 PMis it possible to recompress variable frame rate x264 to constant frame rate (ex: 59.94fps) with Avidemux ?

Use Resampe FPS filter

What OS / monitor display refresh rate / gpu are you using ?

With v2.7.9-dev Switching to video output: OpenGL and restarting Avidemux seems to fix the issue, this isn't the default though (It's not clear to me where the video output property is stored, but the default is dxva2). I'm using  Win10 / Intel Integrated Graphics / 60Hz monitor refresh.

dxva2 was working in v2.7.1 (I'm not sure when this started, but it likely isn't recent).


config3 defaults:
"features" : {
"swap_if_A_greater_than_B" : true,
"saveprefsonexit" : true,
"ignoresavedmarkers" : false,
"reuse_2pass_log" : false,
"audiobar_uses_master" : false,
"threading_lavc" : 0,
"cpu_caps" : -1,
"cache_size" : 16,
"mpeg_no_limit" : false,
"dxva2" : false,
"dxva2_override_blacklist_version" : false,
"dxva2_override_blacklist_profile" : false,
"vdpau" : false,
"xvba" : false,
"libva" : false,
"videotoolbox" : false,
"enable_opengl" : false,
"cap_refresh_enabled" : false,
"cap_refresh_value" : 100,
"sdlDriver" : "",
"use_last_read_dir_as_target" : false
},


I suspect that this is purely a Qt issue, introduced in more recent Qt versions than used in Avidemux 2.7.1. I haven't tested with Qt6 yet.

Avidemux v2.7.1
Compiler: GCC 5.4.0
Build Target: Microsoft Windows (x86-64)
User Interface: Qt (5.8.0)

Quote from: szlldm on April 07, 2021, 08:55:12 PMI have no problem with software decoding (4k 60fps is OK)

I definitely saw this on Linux too, but cannot reproduce with a 1080p 60fps ( = display refresh rate) sample on my main PC now, no matter which video output (decoder should not matter anyway as far as it is capable of decoding the stream in real time with some safety margin).

(This is on Fedora 33 with Qt 5.15.2)

On Fedora 32 with Qt 5.14.2, I get this when using VDPAU hardware decode and VDPAU display.  Change one of those to something else and it doesn't happen.

Which version of NVIDIA graphics driver do you run?

The issue definitely doesn't happen (or doesn't happen anymore) for me on Fedora 33 with the version 460.67 of NVIDIA graphics drivers and Qt 5.15.2. It may be related to a Qt update, it may be related to the graphics driver. As Fedora 32 goes EOL in a few weeks, the outlook is bright.

Quote from: eumagga0x2a on April 27, 2021, 07:15:28 PMWhich version of NVIDIA graphics driver do you run?

AMD.  I guess I will see soon if a Qt update fixes it.