rendering question/issue mp4 versus mov

[Ilene]

Came across a rendering issue/question
I always render my final output to the same Mp4 format -- using these parameters

MPEG-4 Files
24 bits, 1920 x 1080, 29.97 fps
Frame-based
H.264 High Profile Video: 15000 Kbps, 16:9
48000 Hz, 16 Bit, Stereo
MPEG AAC Audio: 192 Kbps

On a recent render, on project created in X8, I noticed some fuzziness on parts of the video, almost like a compression issue. An image would be slightly blurry in the background ( video track) or the overlay image would be fuzzy, and then both would come back into focus.. it was only a minor glitch but the output wasn't nearly as sharp as I'm accustomed to..

Just to compare, I rendered the same project file out to MOV using these settings

QuickTime Movie Files
24 bits, 1920 x 1080, 29.97 fps
Frame-based
H.264
100% Quality, 10 Key Frame Rate
None, 48.000 KHz, 16 bits, Stereo

The output file was perfect CLEAR -- very sharp -- no issues.... except that I noticed certain, well timed effects were slightly off, as if I had a frame rate issue, when both files were rendered at 29.97fps

For instance - An effect that came in at 4:22:24 AS Mp4 ( 29.97), came in at 4:22:17 as MOV - subtle but noticeable difference

I called support and they suggested I render the file out at 30fps MOV, which I did... again, the file was clear -- perfect... and the effect that I wanted to hit at 4:22:24 did hit at 4:22:24....
Very confusing to me that the frame rate was different -- what would be the difference between MOV and Mp4 that would cause this??

The final output files vary slightly different in size.

the orig mp4 ( 29.97) was 15,450 frames and 515.516 seconds in duration
the mov at 29.97 was 15,540 frames and 515 seconds ( a 1/2 second off)
the mov at 30fps was 15,465 frames ( more!) but similar length to orig at 515.5 seconds...

the difference is only noticeable where an image fall exactly on a beat... and sometimes if the music goes boom, boom, boom and I drop the picture in at boom, boom, boom --- this is where you notice the difference.. it's subtle but I see if because I'm dead on when I do it originally. I can't explain it, but at least the 30fps output is workable for me...

Any other insight here would be valuable... trying to understand the nuances so it will help me in the future.

My pref is to use MP4 -- more universal... but MOV is fine too

BTW... same computer... opened the x8 file in x9 and rendered to mp4 with my usual setting and it was all clear... just can't do this as a solution because x8 project is 32bit and contains NB transitions that aren't available in my X9 64bit... both versions are running on my PC. I would have to save as X7, smart package, and open on an older computer to render this project as MP4.

thanks
Ilene

[aljimenez]

Lots of improvements to mp4 file handling for X9; I recommend you move to doing your projects using X9. However I understand your reasons for staying with X8.

One thought is about your source files and the filters you are using in your video compilation. I recommend you share/render your project as close as possible to the source video files.

The mov files you created could be converted to mp4 if you desire mp4 and you need to use mov in order to get what you want in X8.

[Ilene]

Source files are primarily jpgs and stock video files as backgrounds that are primarily mp4 and mov. There is ko other video.
I was mostly questioning the oddities w the frame rates. Trying to understand the different results i received. I assumed the 29.97 mp4 and mov would be timed the same, yet they werent. See my descriptions in orig thread. Thoughts??

Thanks.

Also had considered rendering the mov back tp mp4

[lata]

Hi

Make sure your project properties match your video files properties, F6 the Show Messages option should be selected which should match the project to the first video added to the timeline.

Share- Same as first clip, assuming that is one of your original videos, or Same as Project Settings, again assuming they match your video file.

If you are having some audio sync issues after rendering then try rendering without Smart Render.
Also if using Smart Proxy to edit, remove Smart Proxy before rendering, I did have one instance where SP did affect the render, yes I know that should not happen, but just trying to cover all options.

Maybe a little difficult to decide which format if you are mixing Mov and Mp4 in the same project, I assume you need MP4 as the output?

[Ilene]

Have all this covered..


Trying to ascertain why the mp4 -rendered at 29.97fps was more equal to the mov rendered ar 30fps than the mov at 29.97. See stats above

I always mix mov and mp4 on video track as background videos. These are stock videos - nothing Ive shot. My overlay track is always jpg/bmp or png still images.

I know about matching project setting to output settings but i was also told by support that it doesn't matter. The project settings are supposed to give u a preview into what your output will look like.

I havent changed anything here than what has been working fornmenperfectly thus far.
Only raising the question because x8 produced a glitchy mp4, so I tried kiv.

X9 produced same project as clean/perfeft mp4.

So its not the project or the settings its must be the rendering engine and i guess x8 mp4 isnt that great.

Is anyone else surprised that the fps of the mov at 30fps more closely natches the mp4 at 29.97? Thats what im trying to understand.

Thanks

[aljimenez]

I would bet that even the programmers of the encoders could not tell you why there are discrepancies between different fps. My understanding is that 29.997 is implemented with 3000/1001 which to me says that even small shifts from filters could make an impact of fractions of a second in a lengthy video.

[Ilene]

Im sure its complicated. Thats why im asking. And its jot an audio sync problem. THe image comes in at the exact same spot 4:22:24 in the 29.97 mp4 as the 30fps mov and differed on the 39.97mov where i would have thought that both renderings of 29.97 would have been identical.