Hello,
What are good settings to use when exporting the video to MP4 using VBR that retains image quality and motion?
I capture video's with my mobile and according to Windows explorer it does this with a bitrate of 14Mbps.
In order to reduce the movie size I set the bitrate at 7Mbps while exporting it.
However, does this causes unwanted motion blur?
I thought it was caused by framerate (such as 24fps) and not so much data bitrate?!
Hi Marcus.
You have to realise that each export is a re-encoding and compression of the files being rendered. Ideally to keep the quality of the encoding high, especially if you have done anything to the files other than cut and butt join them as each frame is read, assessed, and decisions made about what data can be thrown away with no (perceivable) quality loss. Sometimes the encoders idea of what is not perceivable is not the same as the editors. Ideally you should export at the same frame rate and resolution as the source files and not mix and match. Resolution though is not just the frame size but the bit depth and amount of bits used per pixel to give accurate colour and tonal balance. This invariably ends with a file larger in data than the original source files creating it. Beyond a certain point though adding additional bits gives no additional benefit. Each export setting will depend on the bit rates and resolution of the original files so no precise answer can be given if you are super fussy as I am. Also setting up wrong settings can produce files with no data or may terminate the export after a while.
The presets in the Export Movie / Video As **** will give you a drop-down list of preset settings that are good enough for most people but can be played around with if you are not happy with the results. You should export at the same frame rate and resolution of the source files to retain quality. A guide to how to alter these settings can be found at the end of your pdf users manual should you need to tweak a preset. It will probably read as gobbledygook at first but after an amount of experience in exporting you may eventually get a hang of it.
Reducing the bit rate does not cause additional motion blur. Motion blur is solely camera movement and settings generated.
What reducing the file size does is reduce the quality of the export as each frame uses less data and more compression is used which will have the effect of softening the image in general as detail gets merged and lost.
Ray.
Hi Ray,
Thank you for the elaborate respons to my question.
I get it that changing anything from the source will deteriorate the quality of it. However, I didn't expect any motion blurs to be incurred while reducing data bitrate. Especially the source doesn't have this motion blur so I suspected it coming from the conversion.
Nevertheless I've set the data bitrate equal to the source bit rate and the motion blur did not appear.
Even though I like to have smaller file sizes but if this isn't possible I will stick to the source bitrate.
Best regards,
Marcus
Hi
As @CubeAce has commented reducing the bitrate does not create motion blur.
However halving the bitrate does create more 'artefacts' as it has less available data per second to encode the video.
Typically this would be seen as a loss of sharpness, 'blockiness' and banding on subtle colour variations such as a blue sky.
The export presets are already optimised for quality vs file size and it is recommended not to change any of the settings.
. . . . I capture video's with my mobile . . . .
Generally mobiles record in Variable Frame Rate (VFR) mode which is known to cause issues in video editors when the minimum and maximum framerates covering a wide range.
Download and install MediaInfo and analyse one of the source clips, see this tutorial on how to setup MediaInfo and analyse a video clip for all the data required.
In the Video section of the analysis - if you see this line:
Frame rate mode: Variable
The video may need converting to Constant Frame Rate (CFR) if the difference between the minimum and maximum values are not within ±4 fps of the frame rate. Most video converters can do the conversion including Handbrake and AviDemux.
HTH
John EB
Forum Moderator
Hi @johnebaker,
Thank you for your added comment on the VFR and tutorial with Mediainfo.
I've checked and indeed my Samsung S10 captures video in VFR as exposed by Medainfo:
Frame rate mode : Variable
Frame rate : 30.000 FPS
Minimum frame rate : 29.920 FPS
Maximum frame rate : 30.090 FPS
Real frame rate : 30.000 FPS
So would I still need to convert this to CFR with Magix Movie Edit?
Hi
The minimum and maximum frame rates are very close to the (target) frame rate' so the video should not need converting unless you are experiencing audio from the clips going out of sync.
John EB
The problem with variable frame rate video is sometimes the frame rate does not vary much because there is a lot of motion within the clip that keeps the frames being refreshed more often, whereas a clip with some motion and some stillness will create larger variation in the variable frame rate. That is what causes the sound to go out of sync over time as the sound file is still recorded at a fixed frame rate regardless of what the image section is doing as sound constantly changes.
Personally I would batch process a whole batch for a project but having said that it seems those with really powerful systems, like Gid (one of our forum members) don't have any problems at all but their computers are way above the average capability of most users computers used on the forums and a lot of the forum members have good computers for 4K video editing.
Ray.
@johnebaker @CubeAce
Very helpful about the information on VFR. I never considered this to be an issue when editing video's just because it all looked good. I can imagine that using VFR will reduce the film size but not knowing that it would have any (serious?) impact on the video editing software per se.
I saw that Premiere pro had an issue in the past with VFR and specifically with audio sync.
Does Magix movie edit also have this feature or does it have a good workaround in regards to possible audio sync issues.
I see that there are options to fix the VFR -> CFR using Handbrake or Shutter Encoder but I think that each step that is added to the processing phase takes more time and may deteriorate the end footage quality.
Hi.
Luckily I can avoid recording in a variable frame rate mode so avoid that particular problem. The extra storage space needed is not a problem as SATA drives are relatively cheap.
HEVC in itself is a good format but on my machine I find it fine for exporting but not so good on importing into the video editing packages I have. The better any additional graphics card is, the less of a problem this appears to be.
I personally have (what I consider by today's standards) is a lower end performance card. For what I try to do I think I need one with a larger pcie bus width and more vram. I copes but jogs along rather than speeds through things. At the moment I'm doing a 48 second project consisting of eight tracks of video only and one sound track. 4k, 50fps, some HD video content (graphics), some Photoshop psd images (for easy transparency and overlaying) and using only brightness and size position on about five objects. Total size of project is 3.03GBs. At present, if I try to alter a parameter of one object I have to wait a minimum of 30 seconds to over a minute before the nvidia 1650 Super has finished doing it's thing and frees the use of my mouse again. I can see the card maxing out its 4GB of vram and adding another 5GB of system reserved graphics memory.
Ray.