How to find out resolution and count of frames in YUV 4:2:0 file if i know how many pixel(luma samples) in the image?
YUV 4:2:0 planar looks like this:
----------------------
| Y | Cb|Cr |
----------------------
where:
Y = width x height pixels (bytes)
Cb = Y / 4 pixels (bytes)
Cr = Y / 4 pixels (bytes)
Total num pixels (bytes) = width * height * 3 / 2
This is how pixels are placed in 4:2:0 sub-sampling:
As you can see, each chroma value is shared between 4 luma-pixels.
Basically, the only thing you can do is to see which frame-sizes divides the total file-size evenly.
As an example, consider the classic forman-clip, which you can download from http://trace.eas.asu.edu/yuv/foreman/foreman_cif.7z
The size of that clip is 45619200 bytes. How do one get the dimensions and number of frames from that? Try different resolutions!
is it SDTV?
In [7]: 45619200 / float(720*576*3/2)
Out[7]: 73.33333333333333
nope!
is it QCIF?
In [8]: 45619200 / float(176*144*3/2)
Out[8]: 1200.0
might be...
is it CIF?
In [9]: 45619200 / float(352*288*3/2)
Out[9]: 300.0
might be...
Only way to find out is trying to display it.
Let's try QCIF
that doesn't look right. Lets try CIF
来源：https://stackoverflow.com/questions/19677747/how-to-find-out-resolution-and-count-of-frames-in-yuv-420-file