What does a constant 30.302 fps frame rate mean?

[Aquinax]

A video created by Powerpoint from a slideshow displays the following information in MediaInfo:

General
Complete name                            : H:\SlideShow 1080 HD.mp4
Format                                   : MPEG-4
Format profile                           : Base Media / Version 2
Codec ID                                 : mp42 (mp41/isom)
File size                                : 42.4 MiB
Duration                                 : 26s 537ms
Overall bit rate                         : 13.4 Mbps
Encoded date                             : UTC 2016-03-19 03:53:08
Tagged date                              : UTC 2016-03-19 03:53:08

Video
ID                                       : 1
Format                                   : AVC
Format/Info                              : Advanced Video Codec
Format profile                           : Baseline@L4
Format settings, CABAC                   : No
Format settings, ReFrames                : 2 frames
Codec ID                                 : avc1
Codec ID/Info                            : Advanced Video Coding
Duration                                 : 26s 537ms
Source duration                          : 26s 533ms
Bit rate                                 : 13.4 Mbps
Width                                    : 1 920 pixels
Height                                   : 1 080 pixels
Display aspect ratio                     : 16:9
Frame rate mode                          : Constant
Frame rate                               : 30.302 fps
Color space                              : YUV
Chroma subsampling                       : 4:2:0
Bit depth                                : 8 bits
Scan type                                : Progressive
Bits/(Pixel*Frame)                       : 0.213
Stream size                              : 42.4 MiB (100%)
Source stream size                       : 42.4 MiB (100%)
Encoded date                             : UTC 2016-03-19 03:53:08
Tagged date                              : UTC 2016-03-19 03:53:08
mdhd_Duration                            : 26532

Audio
ID                                       : 2
Format                                   : AAC
Format/Info                              : Advanced Audio Codec
Format profile                           : LC
Codec ID                                 : 40
Duration                                 : 26s 537ms
Bit rate mode                            : Constant
Bit rate                                 : 25.7 Kbps
Nominal bit rate                         : 192 Kbps
Channel(s)                               : 2 channels
Channel positions                        : Front: L R
Sampling rate                            : 44.1 KHz
Frame rate                               : 43.066 fps (1024 spf)
Compression mode                         : Lossy
Stream size                              : 83.2 KiB (0%)
Encoded date                             : UTC 2016-03-19 03:53:08
Tagged date                              : UTC 2016-03-19 03:53:08
mdhd_Duration                            : 26537

where it is stated the video is encoded in a Constant 30.302 fps frame rate. I have a problem uploading and playing this video on a web portal - some slides consistently stutter or display distortions - and I suspect the strange frame rate of 30.302 to be the cause of it. Whatever does it mean - 30.302 frames per second?

[Adithya]

I'm not sure about that. BUT: Since it is a slideshow converted into a video it may happen.

Why don't you try to repack that video with mp4box and see the mediainfo again.

Download mp4box and copy it to the video folder, open a command window there and type this command

mp4box -add yourvideo.mp4 -new output.mp4

Then check the video's mediainfo and confirm it.

[Adithya]

If you are going to reconvert it then i would suggest either 29.97 or 30.00

[jagabo]

You can create videos with whatever frame rate you want. Software players are pretty flexible when it comes to playing unusual frame rates. If a site like Youtube changes the frame rate from 30.3 to 30.0 fps it will do so by discarding one frame out of every 100, possibly creating a small jerk every ~3.3 seconds. If your video has no audio you may be able to change the frame rate in the header (no reencoding), slowing it down to 30 fps, and increasing the running time by 1 percent.

[Aquinax]

I'm not sure about that. BUT: Since it is a slideshow converted into a video it may happen.

Why don't you try to repack that video with mp4box and see the mediainfo again.

Download mp4box and copy it to the video folder, open a command window there and type this command

mp4box -add yourvideo.mp4 -new output.mp4

Then check the video's mediainfo and confirm it.

What do you mean "copy it to the video folder", mp4box is a 20MB *.exe installer. Could you perhaps provide clearer instructions on how to use mp4box?

[Adithya]

I'm not sure about that. BUT: Since it is a slideshow converted into a video it may happen.

Why don't you try to repack that video with mp4box and see the mediainfo again.

Download mp4box and copy it to the video folder, open a command window there and type this command

mp4box -add yourvideo.mp4 -new output.mp4

Then check the video's mediainfo and confirm it.

What do you mean "copy it to the video folder", mp4box is a 20MB *.exe installer. Could you perhaps provide clearer instructions on how to use mp4box?

I did'nt mean the entire GPAC!! Here copy the content of all of this attachment to the folder.

EDIT: Yeah you were right, my instructions were not very clear, Sorry.

[Aquinax]

Adithya, to put it politely, I'm not sure you know what you're talking about.

[jagabo]

Wow!

[Adithya]

Adithya, to put it politely, I'm not sure you know what you're talking about.

Yeah i was thinking the same thing....

EDIT: I was just answering the question of is it the correct framerate of the file.

The answer to the second question is as jagabo suggested, is to repack the video with the framerate changed to 30 fps in it's header (If there are no audio streams) OP can do that by this ffmpeg command

ffmpeg -i "His Video.mp4" -c copy -r 30 "Output Video.mp4"

[Aquinax]

You can create videos with whatever frame rate you want. Software players are pretty flexible when it comes to playing unusual frame rates. If a site like Youtube changes the frame rate from 30.3 to 30.0 fps it will do so by discarding one frame out of every 100, possibly creating a small jerk every ~3.3 seconds. If your video has no audio you may be able to change the frame rate in the header (no reencoding), slowing it down to 30 fps, and increasing the running time by 1 percent.

Thanks, jagabo,

I think earlier you provided the fraction, by which 30.303 is calculated. I didn't know of it, and what was it again?

[jagabo]

I think earlier you provided the fraction, by which 30.303 is calculated. I didn't know of it, and what was it again?

I don't understand what you're asking. 30.303 fps means each frame is supposed to be displayed for 1/30.303 seconds, about 0.0330000033 seconds. A display running at 60 Hz will display most frames for 2/60 second, but occasionally a frame will be displayed for only 1/60 second so that the average frame rate is 30.303 fps.

[JVRaines]

The answer to the second question is as jagabo suggested, is to repack the video with the framerate changed to 30 fps in it's header (If there are no audio streams) OP can do that by this ffmpeg command

ffmpeg -i "His Video.mp4" -c copy -r 30 "Output Video.mp4"

Your command will discard or duplicate frames to achieve 30 fps, which was the problem to begin with. The -r(ate) option needs to come before the input file:

ffmpeg -r 30 -i "His Video.mp4" -c copy "Output Video.mp4"