ASF container + DirectShowShource = Frame accurate?

Inspector.Gadget · 5th January 2009, 20:15

Hi all, quick Avisynth question. I have a 1440x1080p30 anamorphic VC-1 video in an ASF container that I'd like to frameserve with Avisynth and I'd like to know whether I can expect to run into problems using a filter graph with WMVideo DMO as the VC-1 decoder. Reading the Avisynth Mediawiki, I know I'll at least need to specify the FPS in my script. I think I will also use the same AVS script to serve audio from the original ASF to my encoder. So, questions:

1) Will this work without dropping frames on a fast, modern (Vista) system that plays 1080p VC-1 files with no stuttering? The only other thing I'll be doing in Avisynth is resizing to 1280x720.

2) Would I be better to use Haali's DirectShowSource for the sake of frame accuracy and make a separate DSS script for audio?

Thanks!

qyot27 · 5th January 2009, 21:17

Do you mean using Graphedit (or GraphStudio, if you prefer) to create a .grf file that you'll open with DirectShowSource, or simply opening the file directly with DSS?

1) Dropping frames won't be an issue unless there's some sort of capture software involved. Any of the standard AviSynth source filters should return all detected frames of the video stream. If you're talking about lagging on script playback due to not having enough hardware strength, then maybe it will maybe it won't. But that should hold no bearing on the integrity of the stream's frames on its way to the encoder you're piping it to.

2) As long as the audio can be played via DirectShow, then a separate script wouldn't be necessary. If you are absolutely paranoid about audio sync, then use the convertfps=true option after specifying the fps value, like so (you might need to use Trim if you run into junk frames at the end of the script-served video):

Code:

DirectShowSource("test.wmv",fps=30,convertfps=true)

I'm sure there are more complicated methods, but that's always worked for me.

Inspector.Gadget · 8th January 2009, 20:21

Thanks for the advice, qyot27, that seems to have worked fine on some samples I cut.

5th January 2009, 20:15	#1 \| Link
Inspector.Gadget Registered User Join Date: May 2008 Posts: 1,618	ASF container + DirectShowShource = Frame accurate? Hi all, quick Avisynth question. I have a 1440x1080p30 anamorphic VC-1 video in an ASF container that I'd like to frameserve with Avisynth and I'd like to know whether I can expect to run into problems using a filter graph with WMVideo DMO as the VC-1 decoder. Reading the Avisynth Mediawiki, I know I'll at least need to specify the FPS in my script. I think I will also use the same AVS script to serve audio from the original ASF to my encoder. So, questions: 1) Will this work without dropping frames on a fast, modern (Vista) system that plays 1080p VC-1 files with no stuttering? The only other thing I'll be doing in Avisynth is resizing to 1280x720. 2) Would I be better to use Haali's DirectShowSource for the sake of frame accuracy and make a separate DSS script for audio? Thanks!

5th January 2009, 21:17	#2 \| Link
qyot27 ...? Join Date: Nov 2005 Location: Florida Posts: 1,507	Do you mean using Graphedit (or GraphStudio, if you prefer) to create a .grf file that you'll open with DirectShowSource, or simply opening the file directly with DSS? 1) Dropping frames won't be an issue unless there's some sort of capture software involved. Any of the standard AviSynth source filters should return all detected frames of the video stream. If you're talking about lagging on script playback due to not having enough hardware strength, then maybe it will maybe it won't. But that should hold no bearing on the integrity of the stream's frames on its way to the encoder you're piping it to. 2) As long as the audio can be played via DirectShow, then a separate script wouldn't be necessary. If you are absolutely paranoid about audio sync, then use the convertfps=true option after specifying the fps value, like so (you might need to use Trim if you run into junk frames at the end of the script-served video): Code: DirectShowSource("test.wmv",fps=30,convertfps=true) I'm sure there are more complicated methods, but that's always worked for me.

8th January 2009, 20:21	#3 \| Link
Inspector.Gadget Registered User Join Date: May 2008 Posts: 1,618	Thanks for the advice, qyot27, that seems to have worked fine on some samples I cut.