How to maintain bitrate when editing, plus not need to reduce the FPS??

[Apollo89x]

I have a slightly unusual sequence of how I edit my videos, but it's the only method i've found that works to achieve my end goal-

A. The clips are shot in 50fps (around 27,000 bitrate), and .mp4 format.
I upload the files onto the only editor im comfortable in using the features of (Windows Movie Maker) and do all my editing on it there.
I then save the file, but to maintain the bitrate I set the export settings as 37,000 bitrate and .WMV format (which is CBR, wheras .mp4 is VBR), then save the file.

B. The edited file is then saved as a 37,000 bitrate file.
I then upload that file onto Magix Pro editor, and use the automatic brightness correction feature on there to fix the lighting to being perfect, then I export the file out of Magix back onto my laptop, but in .MP4 format.

The end file is then between 16,500 - 18,000 bitrate (so looks identical same quality as the original 27k), however the issue which I encountered with 2 files using this method was audio went out of sync with video, due to the FPS it seems...


As the files are all shot in 50fps, apart from one which was shot by a different camera in 59fps.
At the end of part A when I save out of Windows Movie Maker I have to specificy what FPS i want to save the file as. I tried to save file 1# with its original 50fps, but the end file after Magix bit was done endedup being a file with out of sync audio!
Did the exact same method all over again, but instead changed the FPS value to export it out of MovieMaker as being 29.97fps (rather than its source 50fps), put that new 29.97fps file through Magix, and the end file ive got is now a 18k bitrate 29.97 file with audio that looks in sync.

However when I just now did that same method with the 59fps file, saved it out of moviemaker at 29.97fps (and 10k bitrate above source), but the audio is out of sync on it.


So my question is was this purely due to this one file having been shot with a different camera?
And that all my normal files which were shot at 50fps, if I export them after edit at 29.97fps will the audio be in sync?

(As my graphics card doesn't have the option to enable hardware acceleration, so it takes many hours to export 1GB files, hence trial-and-error is extremely time-consuming).

[pandy]

So my question is was this purely due to this one file having been shot with a different camera?
And that all my normal files which were shot at 50fps, if I export them after edit at 29.97fps will the audio be in sync?

One simple rule - if audio and video length will be the same then you have perfect synchronization between both (assumption is that your source has video and audio synchronized) - audio and video are two independent things and they must be played with same time speed to keep them synced - this is only one thing they have common - time - remaining things are totally unrelated. Going from 50fps to 29.97 (properly 30000/1001) can be challenging, would rather try to go for 59.94 (60000/1001) speed then (or even 60 fps if feasible on your target player - fractions are unfriendly for digital domain).

[Apollo89x]

Hello and thanks for your reply.

So just to confirm, even though the original video file format is PAL (and 50fps), when I import it onto Windows Movie Maker (which i believe is NTSC software) and then need to export it out of Movie Maker,
the file would look better if I export it at 25fps, rather than at 29.97fps (due to the mathematics of dividing the 50)??

I want the file to play at normal speed and just look normal though too, not to look slower/faster in 25fps than it did at 50fps.

[Bernix]

Hi,
because you said, you have slow computer, you can test it on small piece of video. In avidemux, there is filter to change fps to any fps without changing duration of video. There is also filter that changes fps and duration. So choose the right one. But probably from 60000/1001 to 50fps there can be some problems in final video, but who knows. And result can be to your satisfactory also.
So at least worth to try it on say 1 minute of video.


I used word satisfactory bad not really sure what it exactly means

[Apollo89x]

Hi,
because you said, you have slow computer, you can test it on small piece of video. In avidemux, there is filter to change fps to any fps without changing duration of video. There is also filter that changes fps and duration. So choose the right one. But probably from 60000/1001 to 50fps there can be some problems in final video, but who knows. And result can be to your satisfactory also.
So at least worth to try it on say 1 minute of video.


I used word satisfactory bad not really sure what it exactly means

Hello and thanks for your reply.

I use Windows Movie Maker, and when you change the FPS, the duration of the clip automatically remains the same.
So im guessing that means even if I reduce the FPS, the clip itself will not be in slow-mo or anything?

My main question I guess though is that-
Given the video is shot in PAL format (at 50fps), but then imported into Windows Movie Maker (which is NTSC software), is it better for me to export at 29.97?
Or would it be better for me to export out of Movie Maker at 25fps?


Since because 25 divides into 50, wheras 29.97 doesn't, I worry that the audio may become out of sync with video due to that divisional issue?

[smrpix]

Well aware that I'm treading into awful comment territory.

But seriously, if you use Windows Movie Maker you could be up to speed doing all your editing in Magix in about a half hour. That would save you steps and re-compressions, etc.

Submitted respectfully.

[jagabo]

Don't use WMV3/9 for your intermediate file. That codec is inherently variable frame rate. And many editors will not account for that. It is probably the cause of your A/V sync errors.

[jagabo]

My main question I guess though is that-
Given the video is shot in PAL format (at 50fps), but then imported into Windows Movie Maker (which is NTSC software), is it better for me to export at 29.97?
Or would it be better for me to export out of Movie Maker at 25fps?

50 to 29.97 is better than 50 to 25 to 29.97. Even better would be to convert everything to 59.94 fps.

[Apollo89x]

My main question I guess though is that-
Given the video is shot in PAL format (at 50fps), but then imported into Windows Movie Maker (which is NTSC software), is it better for me to export at 29.97?
Or would it be better for me to export out of Movie Maker at 25fps?

50 to 29.97 is better than 50 to 25 to 29.97. Even better would be to convert everything to 59.94 fps.

Hello and thanks for your reply.

I don't convert from 29.97 to 25fps ever though.

I convert from 50fps to 29.97fps, and then it remains at 29.97.

However would the video play better/look better if I instead converted it from 50fps to 25fps (even though I'm using Windows Movie Maker which is NTSC software), and then just left it at 25fps?

[jagabo]

I convert from 50fps to 29.97fps, and then it remains at 29.97.

However would the video play better/look better if I instead converted it from 50fps to 25fps (even though I'm using Windows Movie Maker which is NTSC software), and then just left it at 25fps?

50 to 25 will look play smoother than 50 to 29.97. WMM isn't NTSC software. It's frame rate agnostic.

[Apollo89x]

I convert from 50fps to 29.97fps, and then it remains at 29.97.

However would the video play better/look better if I instead converted it from 50fps to 25fps (even though I'm using Windows Movie Maker which is NTSC software), and then just left it at 25fps?

50 to 25 will look play smoother than 50 to 29.97. WMM isn't NTSC software. It's frame rate agnostic.

Thankyou so sooo much for confirming this for me!

Providing what you have said is definitately accurate, well that will be massively helpful for me.


Thankyou so much.

[jagabo]

But why don't you just leave your video at 50 fps?

[Apollo89x]

But why don't you just leave your video at 50 fps?

I tried that, but when i do it causes the audio/video to become out of sync when I play the footage.

[jagabo]

But why don't you just leave your video at 50 fps?

I tried that, but when i do it causes the audio/video to become out of sync when I play the footage.

Were you using WMV? As noted earlier, that's not a good format for an intermediate file.

[pandy]

But why don't you just leave your video at 50 fps?

I tried that, but when i do it causes the audio/video to become out of sync when I play the footage.

It may be related to or to slow computer or difference between source framerate (your case 50fps) and display framerate (60fps for example) then you may see some issues (perhaps your player trying to match source and display speed i.e. live framerate correction).

And as many earlier - avoid WMV - it is variable frame rate video codec, also there is no such things as CBR video codec - every video codec is VBR only bitrate is controlled more strict on CBR (and some additional so called stuffing can be add to create very strict CBR).

For slow computer i would check what options do you have - perhaps you can use codec that can be accelerated by your HW thus remove some speed limitations - from at least decade computer HW can accelerate video decoding significantly reducing required CPU power. Perhaps you can start using proper software to remove some limitations preventing you to use source file correctly.

All above is highly hypothetical as there is very low amount of information about your source and your environment.

For sure you should avoid WMV.