VirtualDub2

[jay123210599]

Originally Posted by LigH

VirtualDub2 is an editor, not a media player. I don't see much sense in changing the playback speed only, independent of the nominal frame rate.

So it's not possible?

[SeeMoreDigital]

Not in the way you want to use it. No!

[LigH]

If you have a stack of complex video filters, you can be happy when it still plays in normal speed. Usually it can't keep up anymore.

Being able to check the filtering result frame by frame is much more important in an editor than fast-forward playback.

If you want to skip 50 frames button by button, hold the Alt key. Or pull the timeline slider with the mouse.

[wonkey_monkey]

If you turn the scene thresholds off in Preferences, you can use shift-ctrl-arrow to play as fast possible.

[jay123210599]

Originally Posted by LigH

Video - Frame Rate... - Change frame rate to (a higher value); but this will probably mess up the audio, if present. And the result may not match a secondary format specification.

I doubled the frame rate for one of my videos but it didn't double its speed.

[SeeMoreDigital]

Originally Posted by jay123210599

I doubled the frame rate for one of my videos but it didn't double its speed.

Did you re-encode the video? What media player are you using?

[jay123210599]

Originally Posted by SeeMoreDigital

Did you re-encode the video? What media player are you using?

Yes, I'm playing the video in VirtualDub2?

[SeeMoreDigital]

With respect... You're exhausting!

[LigH]

VirtualDub2 will not skip frames to ensure the frame rate during playback. It will prefer to show every frame, even if it will fall behind the timing.

Media players may do the opposite, e.g. skip decoding B frames and restrict themselves to displaying only I and P frames if that is necessary to keep up the desired playback speed.

[StainlessS]

Originally Posted by LigH

VirtualDub2 will not skip frames to ensure the frame rate during playback. It will prefer to show every frame, even if it will fall behind the timing.

Set (tick) Drop Frames When Behind (its not ticked in below graphic, just shows you where it is)
[click me]


EDIT: Not sure, maybe have to also UnTick "Sync To Audio" (above 'Drop Frames When Behind').

[rgr]

Should I only have the "Cache input driver" to choose from when opening MP4 files?

I've never paid much attention to it, but I remember there used to be others (like "FF-something").

[LigH]

There is a separate AVI source filter compatible with the ancient roots of VfW.

And there may have been input plugins for earlier VirtualDub versions which developed into the current ffmpeg based "Cached input driver", I believe...

[rgr]

Thanks. So its normal.


Another problem.

I have a file compressed with ffmpeg -c:v libx265.
So it's probably correct. It has a rather unusual framerate, "fpsnum=59972,fpsden=1000)"

VirtualDub (the latest test version and the previous one as well) won't read it, crashing on frame 453 during playback.
When jumping to the end of the file and rewinding frame by frame, you can see that the last frames are duplicates (even though they aren't).
MPC plays correctly.

File: https://files.fm/u/24bvfbgf45

Edit: I tested it with version VD 44282. It works fine there, no issues. Both with "Cache input driver" and with "FFmpeg (supported files)"

[rgr]

VirtualDub ignores the _Matrix and _ColorRange flags when loading AviSynth scripts (it always assumes they are BT601 and limited).

I don't know if this will help, but for ffmpeg to recognize these flags, you need to use: ffmpeg.exe -avisynth_flags +all -i... .

[qyot27]

Originally Posted by rgr

I don't know if this will help, but for ffmpeg to recognize these flags, you need to use: ffmpeg.exe -avisynth_flags +all -i... .

ffmpeg enables 6 out of the 7 current frame property flags by default, -avisynth_flags isn't necessary unless you want to turn them off.

The only flag that ffmpeg does not enable by default is SAR, because that one relies on much more user awareness considering how common it is to resize things in AviSynth scripts.

$ ffmpeg -h demuxer=avisynth
ffmpeg version r119297+62 master-ff9f3fb607 HEAD-1483607de1
 contains: avs_pixfmts datetime merged new_pkgconfig silent_invoke versioninfo 
 Copyright (c) 2000-2025 the FFmpeg developers
  built on Apr 18 2025 19:33:33 with gcc 14 (Ubuntu 14.2.0-19ubuntu2)
  libavutil      60.  1.100 / 60.  1.100
  libavcodec     62.  0.101 / 62.  0.101
  libavformat    62.  0.100 / 62.  0.100
  libavdevice    62.  0.100 / 62.  0.100
  libavfilter    11.  0.100 / 11.  0.100
  libswscale      9.  0.100 /  9.  0.100
  libswresample   6.  0.100 /  6.  0.100
  libpostproc    59.  1.100 / 59.  1.100
Demuxer avisynth [AviSynth script]:
    Common extensions: avs.
AviSynth demuxer AVOptions:
  -avisynth_flags    <flags>      .D......... set flags related to reading frame properties from script (AviSynth+ v3.7.1 or higher) (default field_order+range+primaries+transfer+matrix+chroma_location)
     field_order                  .D......... read field order
     range                        .D......... read color range
     primaries                    .D......... read color primaries
     transfer                     .D......... read color transfer characteristics
     matrix                       .D......... read matrix coefficients
     chroma_location              .D......... read chroma location
     sar                          .D......... read sample aspect ratio

Script:

ImageSource("GsKynKVaUAI7COX.jpeg").Crop(0,0,0,-1).ConvertToYV12()
propset("_FieldBased",0)
propset("_Primaries",4)
propset("_Transfer",4)
propset("_Matrix",4)
propset("_ChromaLocation",2)
propset("_ColorRange",0)
propset("_SARNum",4) # this and SARDen set to nonsense just to show whether it gets read
propset("_SARDen",3)

(-v verbose is only needed because ffmpeg doesn't include the chroma location value in the report otherwise)

ffmpeg -v verbose -i test.avs

Input #0, avisynth, from 'test.avs':
  Duration: 00:00:41.71, start: 0.000000, bitrate: 0 kb/s
  Stream #0:0: Video: rawvideo, 1 reference frame (I420 / 0x30323449), yuv420p(pc, fcc/bt470m/bt470m, progressive, topleft), 680x254, 24 fps, 24 tbr, 24 tbn

ffmpeg -v verbose -avisynth_flags +all -i test.avs

Input #0, avisynth, from 'test.avs':
  Duration: 00:00:41.71, start: 0.000000, bitrate: 0 kb/s
  Stream #0:0: Video: rawvideo, 1 reference frame (I420 / 0x30323449), yuv420p(pc, fcc/bt470m/bt470m, progressive, topleft), 680x254, SAR 4:3 DAR 1360:381, 24 fps, 24 tbr, 24 tbn

[jay123210599]

How do I mirror videos in VirtualDub2?

[LigH]

Video - Filters - Add: flip horizontally / flip vertically

[v0lt]

Originally Posted by rgr

VirtualDub (the latest test version and the previous one as well) won't read it, crashing on frame 453 during playback.
When jumping to the end of the file and rewinding frame by frame, you can see that the last frames are duplicates (even though they aren't).
MPC plays correctly.

File: https://files.fm/u/24bvfbgf45

VirtualDub2 x64 v2.4.0.877 - no problem.

Originally Posted by rgr

VirtualDub ignores the _Matrix and _ColorRange flags when loading AviSynth scripts (it always assumes they are BT601 and limited).

I don't know if this will help, but for ffmpeg to recognize these flags, you need to use: ffmpeg.exe -avisynth_flags +all -i... .

As far as I remember, VirtualDub/VirtualDub2 (like many other applications) work with AviSynth scripts as with a virtual AVI file (system components are used).
For this reason, VirtualDub does not receive additional video stream parameters.
See the description of the VIDEOINFOHEADER and BITMAPINFOHEADER structures.

[rgr]

Originally Posted by v0lt

VirtualDub2 x64 v2.4.0.877 - no problem.

Are you sure?
What about this file? https://files.fm/u/mywfgz46nj (it's short, so sometimes you have to jump to the end several times and go back frame by frame)
This appears to be a problem with H265 files with open GOP.

The effect should be like:
this.https://gcdnb.pbrd.co/images/Q3xlj4A5fmA2.png?o=1

[rgr]

Originally Posted by v0lt

As far as I remember, VirtualDub/VirtualDub2 (like many other applications) work with AviSynth scripts as with a virtual AVI file (system components are used).
For this reason, VirtualDub does not receive additional video stream parameters.
See the description of the VIDEOINFOHEADER and BITMAPINFOHEADER structures.

Bad news...
However, VDub can probably abandon the default BT601, or at least apply the rule that if the height is >=720px, BT709 is assumed.
At least some information about the decoding format (BT601/709/RGB, limited/full range, etc.) on the bottom bar would be useful