FrameRate Issue

Gaming and Visualization Technologies Video Processing & Optical Flow
1

Hello.

I’ve using ‘Video_Codec_SDK_11.1.5’.
I have problem with to get frame rate of the specific video file.

When I play with ‘ffmpeg’, ‘vlc’, that’s codec info show 30fps and ‘MediaInfo’ shows same.
It’s info of that video’s ‘MediaInfo’.

image
image255×501 8.31 KB

This is from 'FFmpeg".

Metadata:
  major_brand     : isom
  minor_version   : 512
  compatible_brands: isomiso2mp41
  encoder         : Lavf58.12.100
Duration: 00:48:06.23, start: 0.000000, bitrate: 2171 kb/s
Stream #0:0[0x1](und): Video: mpeg4 (Advanced Simple Profile) (mp4v / 0x7634706D), yuv420p, 640x480 [SAR 1:1 DAR 4:3], 2054 kb/s, 30 fps, 30 tbr, 15360 tbn (default)
  Metadata:
    handler_name    : VideoHandler
    vendor_id       : [0][0][0][0]
Stream #0:1[0x2](und): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz, stereo, fltp, 110 kb/s (default)
  Metadata:
    handler_name    : SoundHandler
    vendor_id       : [0][0][0][0]

And real fps of that video file is 30.

But,
On NvDecoder, was 3fps get.
→ m_videoFormat.frame_rate.numerator : 30
→ m_videoFormat.frame_rate.denominator : 10

This is output of “GetVideoInfo()”

	Codec        : MPEG-4 (ASP)
	Frame rate   : 30/10 = 3 fps
	Sequence     : Progressive
	Coded size   : [640, 480]
	Display area : [0, 0, 640, 480]
	Chroma       : YUV 420
	Bit depth    : 8
Video Decoding Params:
	Num Surfaces : 4
	Crop         : [0, 0, 0, 0]
	Resize       : 640x480
	Deinterlace  : Weave

How can i get real fps from this video?
Do I have to modified fps formula for each video codec?

2

Hi there!

You are using the sample code on our github page, correct? It might just be that you have found a bug either in the sample app or in the way we report the frame rate (de)nominator.

Would it be possible for you to share an example video where you encounter this issue?

Thanks!

3

denominator should be 1.

4

Hi, can I somehow get a sample file? Thanks.