Yahoo Answers is shutting down on May 4th, 2021 (Eastern Time) and beginning April 20th, 2021 (Eastern Time) the Yahoo Answers website will be in read-only mode. There will be no changes to other Yahoo properties or services, or your Yahoo account. You can find more information about the Yahoo Answers shutdown and how to download your data on this help page.
Trending News
Framerate issues, Sony Vegas, Canon Camcorder?
The short question: How can I make Sony Vegas drop every 5th frame to go from a "bogus" 24p (that's actually 24p with a duplicate frame once every 5 frames), to real 24p.
The long story: I have a Canon HF M40 camcorder that I am very impressed with, for the most part. The issue I have with it is that it can capture video at 60i, 30p, or 24p framerates, BUT encodes all three of those as 60i. This has caused me a bit of trouble and confusion. I like to use the 24p mode to go for more of a cinematic look as opposed to the smoother look of 30p or 60i. And, I want the final product to be progressive, not interlaced, as it is destined for Youtube. What I have been doing is filming in the 24p setting, importing all the AVCHD clips (with 24p encoded as 60i) into Sony Vegas 11 with project settings as "1920x1080 29.97i", and then rendering them all as one big 24p file, which I can then edit. Vegas seems to do fine with de-interlacing the 60i down to 24p, BUT, there is noticeable "ghosting" in shots with motion. And I'm not talking about the motion blur that is to be expected with 24p. Vegas doesn't seem to be handling the footage properly. This is my best theory as to what is going on:
Ok, so normal 60i is 60 "fields" of alternating lines per seconds, or 30 frames per second with each frame made of two fields. The fields are 1/60th of a second apart in timing.
On this camera in 30p mode, the video is captured as 30 progressive frames per second, and then each frame is split in half into two fields for the 60i encoding. However, the two fields' times are exactly the same, so Vegas easily merges them into one frame, to go back to the original 30p.
24p is where things get tricky. What seems to happen is that the camera captures 24 progressive frames per second and then does the same trick with duplicating the fields, BUT it throws in a duplicate frame (or set of fields) once in every 5 frames (which makes sense because this is the ratio between 24p and 30p). I can verify this during the playback by going frame by frame. There will be 4 frames and then the 4th repeated.
So, the bottom line is this: When you're converting from 30p to 24p, you usually either risk the ghosting or have to drop frames and things get choppy. But, the frames I would be dropping are duplicate frames, so it should remain smooth. I don't know how to tell Vegas which ones to drop, though.
Any help on this bizarre business with 24p encoded as 60i would be appreciated.
Update:
To make things even more bizarre and confusing, I was able to successfully export a clip of the 24p-as-60i footage as proper 24p with no ghosting, interlacing, duplicated frames, or dropper frames. The weird thing is, I can't figure out how I did it. I tried to repeat the same procedure again with no luck.
The good news is, this shows that what I'm trying to do CAN be done - I made it work once. The bad news is, I can't figure out what exactly I changed to make this work.
In regards to lare's answer:
I can count the individual frames on a 29.97p timeline on Vegas - there aren't only 3 a second. It's set up like a 2:3 pulldown. So, I need to perform IVTC on the footage, but Vegas doesn't seem to be doing this properly.
One more thing for lare:
I bring the AVCHD files into Vegas and then export as a XDCAM EX .MP4 format with 23.970p setting. I'm not trying to export them as AVCHD files.
4 Answers
- Anonymous10 years agoFavorite Answer
Sony Vegas I think it is better
- lareLv 710 years ago
your premise that "the camera captures 24 progressive frames per second" is bogus. Because AVCHD has a fixed GOF of 8, it in fact records only 3 actual frames per second in the 24p mode. The missing frames are virtual, the player has to make interpolation guesses to fill in, and that is the cause of the "ghosting" problem. You would be best served by shooting in 60i originally as this will give Vegas the most actual video to work with plus interlace gives it a better clue as to how to interpolate motion. Stay in that mode through the editing cycle and then convert to 24p on the published version. FYI you will get superior results by publishing in MPEG2 which does not use a fixed GOF of 8 like AVCHD and MPEG4. MPEG2 is the codec used for HDTV.
- 10 years ago
For me, the simplest way was by using the plugin neoscene which converts the footage to true 24p and actually turns footage into 10 bit 24p files with no extra frames
- ?Lv 44 years ago
The manufacturers with the terrific reputations and camcorder products are Sony, JVC, Panasonic and Canon. no longer unavoidably in that order, those 4 even have broadcast divisions, in assessment to turn or Sanyo. Canon is a overdue comer to the published camcorder celebration so because it somewhat is the only type I surely have not individually owned, yet they have produced broadcast digital camera lenses for the different manufacturers for some years.