View Full Version : How to quickly tell if CF video is I-Frame or not.
Stephen Armour August 22nd, 2010, 01:37 PM David, I have a question. I've been trying to find a quick tool that tells whether video we've done is I-frame only only or not. G-Spot shows nothing about it that I can tell, neither does VD or anything else.
We have a mixture of stock that is both ways and really need something that tells which way it is so we can re-convert whatever we are currently working on.
Any suggestions as to a quick (and free) tool that does it?
David Newman August 22nd, 2010, 02:50 PM The only reason to worry about I-frame, is for 3D work, otherwise is it completely transparent all 99% of video applications. Use VirtualDub, is will mark I-frame with a 'K' (for Key frame) and P frames with nothing.
Stephen Armour August 23rd, 2010, 09:57 AM That's exactly what I was looking for and could find no info anywhere!
Tnx!
Stephen Armour August 23rd, 2010, 11:01 AM The only reason to worry about I-frame, is for 3D work, otherwise is it completely transparent all 99% of video applications. Use VirtualDub, is will mark I-frame with a 'K' (for Key frame) and P frames with nothing.
For our output for international dubbing and subtitle translators, the frame accuracy of the I-Frame only in First Light is crucial. We need every frame properly referenced to our target master AVI, and I-frame only is the only way we know how to do using FL for the different videos. This was especially true for our material that was CF'ed from HDV tape, since FL didn't show the timecode at the same rate for that HDV material, unless we re-output it as I-Frame only.
Bruce Gruber August 24th, 2010, 03:55 AM Stehpen or Dave while we are at it. What tool tells you if CF file is interlaced or progressive. I have some CF files that I do not know if they are progressive or not. G-spot does not seem to give the info on a cf file.
Stephen Armour August 24th, 2010, 07:29 AM Bruce, here's a post from another forum that tells you why this is a complicated subject:
How can I tell if a video is interlaced? (http://forum.videohelp.com/threads/272991-How-can-I-tell-if-a-video-is-interlaced)
There are many things to consider and no hard answers to that question...unfortunately.
Jay Bloomfield August 25th, 2010, 04:47 PM As the link you attached states, the only way that you can tell with an AVI file, is by looking at the individual frames with something like VirtualDub.
I think I suggested this to David Newman before, but with all the extra metadata that Cineform is putting in the files these days, they should consider adding an interlaced/progressive metadata entry. Now, no NLE would be able to directly use this information, since they don't read the Cineform special metadata, but at least the information could be displayed in First Light. Of course, this approach only would work if the user explicitly stipulated "Interlaced" or "Progressive" output when either capturing or converting to CFHD. The "Automatic" setting wouldn't be of any help. BTW, there are other threads that discuss this issue and also the related issue of determining whether a file is 24p in a 60i stream.
Stephen Armour August 25th, 2010, 08:15 PM Good idea Jay, I second the motion. Maybe it'll start adding something useful to us down the line...
Stephen Armour August 25th, 2010, 08:20 PM The only reason to worry about I-frame, is for 3D work, otherwise is it completely transparent all 99% of video applications. Use VirtualDub, is will mark I-frame with a 'K' (for Key frame) and P frames with nothing.
One more comment:
In VD, you have to "frame by frame advance" to see if it's I-frame only. If it is, every frame has the K. If not, every other frame has the K.
Graham Hickling August 25th, 2010, 09:49 PM I can recommend the Viewfields plugin for Virtualdub:
[NEW LINK] http://www.geocities.com/siwalters_uk/viewfields.html
This plugin separates each video frame into two half-height "fields" and stacks one above the other - if they are identical the frame is progressive, if they differ you'll easily see which order the fields are in.
Stephen Armour August 26th, 2010, 06:16 AM Graham, the downlink is no longer working for that file now. Guess they pulled it.
Graham Hickling August 26th, 2010, 07:01 AM Oops - sorry. Here's a link to the plugin developer's webpage. The Virtualdub version is on the left, the Avisynth version is on the right.
http://www.geocities.com/siwalters_uk/viewfields.html
Stephen Armour August 26th, 2010, 10:58 AM Thanks for the new link, Graham, but apparently that filter is still 32bit and I'm running the 64bit version of VD. I tried loading it from the Plugin directory and directly and it doesn't accept it.
Graham Hickling August 26th, 2010, 12:06 PM OK, sorry. I'm on 64bit Win7, but I 'm using the 32bit version of VDub.
(You could likely have both VDub versions on your system, since VDub doesnt install any dlls)
Jay Bloomfield August 26th, 2010, 05:36 PM Here's a slightly more elaborate plugin for Sony Vegas Pro:
Sony Creative Software - Forums - Vegas Pro - Video Messages (http://www.sonycreativesoftware.com/forums/ShowMessage.asp?ForumID=4&MessageID=671710)
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