Double PAL framerates, AVFS, and Vegas. Video playing back doublespeed.

[banditeer]

Hi all,

Thanks again to all who helped sort out the color matrix import problem in vegas for me. That side of things is working fine now, but I'm having trouble with playback speed/framerate. Original mts file is double pal (50fps, altho its actually only 25 but every frame is repeated). Properties in vegas is set to 50fps, and render settings is set to 50fps. With the settings like this there has been no problem with playback speed when importing the mts file direct into vegas.

Now I'm coming in thru an avs script, then AVFS, playback of resultant rendered file is double speed. My avs script is simply directshowsource then converttorgb. When I playback the script itself in MediaplayerHC, it plays back correct speed, which inclined me to think the script was correct? And when I play back the dummy avi file created by AVFS that also plays back correctly as well. Is it something to do with AVFS?

[poisondeathray]

is this avchd lite ?

the frame repeat flag causes difficulty with most decoders

use ffmpegsource2, which works for avchd lite

http://code.google.com/p/ffmpegsource/

e.g.
ffmpegsource2("video.mts", atrack=-1)

[banditeer]

Hi poisondeathray,

i couldn't get ffmpegsource2 to work but ffvideosource does. And successfully plays back at the correct speed after encoding! Hoorah!

Confused about one thing tho - I thought ffvideosource was dependant on the ffms2.dll plugin that comes with ffmpegsource, yet when I remove ffms2.dll, ffvideosource in the avs script still works. Is ffvideosource nothing to do with ffmpegsource? When playing back the avs script in mediaplayerHC, no decoding items appear in my systray, so what is doing the decoding when I use ffvideosource?

[poisondeathray]

It's not the same thing as ffdshow, show no decoding items are supposed to appear in the tray

when you remove ffms2.dll, it shouldn't work at all - I don't know what's going on

ffmpeg2source() is a wrapper function for

vid=ffvideosource()
aud=ffaudiosource()
audiodub(vid,aud)

for some reason, the newer versions don't have the ffms2.avsi bundled, you can download it from older versions

or I'll upload it here for you

[banditeer]

So ffvideosource in the script shouldn't work at all if ffms2.dll is not present (as I thought)? That's weird. I'll have a look into it...

[poisondeathray]

yes it should NOT work if ffms2.dll isn't in the avisynth\plugins directory , or if it's not loaded manually by LoadPlugin()

It might be loaded into memory; if you close all applications except the media player playing the .avs file, does it still work?

what about opening avs file in vdub or avsp instead of a media player ?

[banditeer]

Ok that was interesting... I didn't delete ffms2.dll, just changed the extension, thinking that avisynth would then not see it (often do this in audio apps), but avisynth does still see it. After deleting ffms2.dll the avs script indeed no longer plays. Weird.

So is libavcodec doing the decoding then when I use ffvideosource?

[poisondeathray]

yes, ffms2 is compiled with libavcodec

use the ffms2-mt version for more speed on multicore CPU's

(just like in ffdshow, which also use libavcodec, if you use ffmpeg-mt , it will use multithreading)

[Gavino]

I didn't delete ffms2.dll, just changed the extension, thinking that avisynth would then not see it (often do this in audio apps), but avisynth does still see it. After deleting ffms2.dll the avs script indeed no longer plays. Weird.

This appears to be due to a 'feature' of Windows folder searching.
See this Doom9 thread:
http://forum.doom9.org/showthread.php?t=149193

The result is that Avisynth will load any file whose extension starts with "dll" (perhaps because files with long names or extensions also have a short name for DOS compatibility). So to stop a dll from being loaded without deleting it, change the extension to "_dll", for example, or add a further extension like ".old".

[banditeer]

That's interesting info Gavino - thanks. Explains the behaviour.

Ffvideosource seems to be working ok apart from a few frames at the very beginning with strong artifacts. Is this some sort of known issue?

I've also tried ffvideosource, followed by ffaudiosource, then audiodub(v,a), THEN converttorgb after that. That seems to be working ok (apart from same first few frame artifact problem).

[poisondeathray]

no known issues ;

is it possible the stream is damaged? or did you process or cut it in some fashion ?

do the same frames have artifacts with directshowsource ? (despite the frame repeats and or time errors ?)

[banditeer]

Yes the clip that was showing artifacts on the first few frames with ffvideosource was indeed cut, using h264ts_cutter I think. Is there a more relaible cutter? The same clip however show's no problems at the start with directshowsource. Unusual? Tried ffvideosource on other uncut clips and seems to be fine...

[poisondeathray]

It definitely sounds the artifacts occur because of the way you cut it.

A bit unusual, I would expect every decoding method to show the same artifacts; and especially since both use libavcodec

Unfortunately there aren't any reliable cutters; and most of them probably will have issues with avchd lite. tsmuxer may be a bit more reliable, but there is no preview (cut by timecode). Videoredo 4 beta might work , it even smart renders, but it was buggy last time I tested it - I doubt it supports avchd lite properly since it barely works properly with more common h264 formats

You can cut in your avs script as well , using trim() . AVSP is a great tool to use with avs scripts

And since you're frameserving into vegas, why not cut in vegas ?

[banditeer]

Yes cutting in vegas is prob what I will do. The camera itself also allows you to trim footage so may experiment a bit with this as well. Thanks again for your help...