Flickering output from FAVC

[mats.hogberg]

<split off from other thread, so may look a little odd>
I had exactly the same effect (flickering grey) doing a bog std AC3/XviD to DVD using FAVC. Went away after 5 secs.

/Mats

[guns1inger]

Odd, ain't it. I left the same file converting with ConvertXtoDVD when I left for work this morning. Just checked it and the image is fine and the audio in sync. There is no such thing as the perfect conversion software.

[Mr_Odwin]

FAVC uses Avisynth's DirectShowSource and QuEnc/HCenc for mp4s.
If manually you can get a better result using these tools then I'd be happy to implement a fix.
I've not seen the problem you mention but I'm eager to fix it if you can find the root.

[mats.hogberg]

Can't be of much assistance, as I found it a minor problem, and erased both source & dest after watching.
It's just that the in first few seconds of the output video, every other frame seems to be a solid dark grey. The FAVC I used was the version available for DL saturday last week, and I used HCEnc as encoder. AFAICS, the problem may as likely be in HCEnc as well as in FAVC.

/Mats

[guns1inger]

I am seeing exactly the same from the latest available build. I also have the latest FFDShow and Haali Splitter. I still have the scripts from the last problem attempt, and think I have found the problem.

The DirectShowSource statement includes the parameter ConvertFPS=True. If I remove this, I don't get the flickering gray screen.

I wonder if this causes problems when the framerate isn't variable ? Or perhaps it needs to be paired with an actual framerate ? I will test that now.

OK

Removing the ConvertFPS=True from the DirectShowSource statement resolves the issue.
Adding fps=25 tot he DirectShowSource statement with ConvertFPS=True reduces the problem to the first couple of frames.
Removing the ConvertFPS(25,1) statement makes the problem last longer, however it does resolve after about 15 seconds.

I don't know if this is related specifically to the video source in question, or is a bigger issue. That Mats is having it with standard Xvid files, as well as the problems I have had with H.264 based .MKV and .MP4 files would indicate it is bigger.

[mats.hogberg]

I can add that my source was 23.976 fps, and I set output to PAL. Perhaps something to do with frame rate conversion?
I'm splitting this off as a separate thread, as we're threadjacking here.

/Mats

[guns1inger]

Fair call.

[Mr_Odwin]

Is the flickering evident when the avisynth script files are used in something like virtualdub, or is it just the produced m2v files that flicker?

[guns1inger]

I tested the avisynth files in virtualdubmpeg2 and reproduced the flicker. It is definitely coming out of avisynth. I am running avisynth 2.5.7 here.

[Mr_Odwin]

I've asked about this over in the Avisynth Development forum at doom9, and have been told that it is a 2.5.7 bug that is fixed in the 2.5.8 Alpha 1 version of Avisynth.

http://sourceforge.net/project/showfiles.php?group_id=57023&package_id=105994

Care to try it out anyone? (I realise that alpha software isn't everyone's cup of tea.)

[Alex_ander]

Mr_Odwin, does FAVC always write fps=... + convertfps=true for DirectShowSource? How the numbers to write for 'fps=...' are determined?
When manually writing the opening line I often have to take care of correct numbers. If nothing is written for fps, for some types of file (like flv, asf, rm) there are chances AviSynth will use a wrong value (other programs, even MediaInfo also can give wrong numbers for some files). Then in case 'convertfps=true' is not used some frames in the beginning and in the end can get grey and even parts of video can be repeated to fill duration time of video. If 'convertfps=true' is used together with wrong fps number, then video gets repeated frames (or maybe the effect discussed here) while with correct fps number written and 'convertfps' off everything is fine.
After experimenting with numerous files (with framerates like 12, 12.5, 15, 25) I took it as a rule for myself to find correct fps experimentally (since there's no an absolutely reliable way), write it to DirectShowSource line and avoid using convertfps at this unless I know it's a VFR video. For some files with unrepairable seekability also seekzero=true is necessary, one more difficulty for a frontend program. Maybe some buttons for adjustment to file properties are needed or a manually created script loaded in such cases.
BTW, what people say about that AviSynth bug?

[Soopafresh]

No flickering seen with 2.58 . I believe the only file which really needs to be changed is DirectshowSource.dll, so those of you who are hesitant, download this, rename your DirectShowSource.dll in your \plugins folder and replace with this one.



directshowsource.zip

[Mr_Odwin]

Mr_Odwin, does FAVC always write fps=... + convertfps=true for DirectShowSource? How the numbers to write for 'fps=...' are determined?
When manually writing the opening line I often have to take care of correct numbers. If nothing is written for fps, for some types of file (like flv, asf, rm) there are chances AviSynth will use a wrong value (other programs, even MediaInfo also can give wrong numbers for some files). Then in case 'convertfps=true' is not used some frames in the beginning and in the end can get grey and even parts of video can be repeated to fill duration time of video. If 'convertfps=true' is used together with wrong fps number, then video gets repeated frames (or maybe the effect discussed here) while with correct fps number written and 'convertfps' off everything is fine.
After experimenting with numerous files (with framerates like 12, 12.5, 15, 25) I took it as a rule for myself to find correct fps experimentally (since there's no an absolutely reliable way), write it to DirectShowSource line and avoid using convertfps at this unless I know it's a VFR video. For some files with unrepairable seekability also seekzero=true is necessary, one more difficulty for a frontend program. Maybe some buttons for adjustment to file properties are needed or a manually created script loaded in such cases.
BTW, what people say about that AviSynth bug?

When using DirectShowSource() the fps argument is taken from MediaInfo.dll, if it can provide it. It is then used with convertfps. If fps isn't provided then convertfps is used on its own.
In the Advanced Scripting tab of FAVC you can choose "Don't Start Batch File". Then you can fiddle with the scripts, ini files and batch file until it is the way that you really want it. For advanced users I like to think of FAVC as generating a template that can be altered rather than it being a complete solution. (What one-click application can really be a complete solution!?!)

[guns1inger]

Excellent work.

[guns1inger]

OK, quick update : replacing just the DirectShowSource.dll file had the same effect as adding fps=25 to the DirectShowSource statement. There was still some flickering, but it was only in the first few frames.

Completely updating to 2.5.8 has fixed the flicker problem.

Now, just how alpha is 2.5.8 alpha ?

[Soopafresh]

I've used it for 2-3 months and no visible problems.