Whether you are going to use YUVPlayer, YUVConvertor, YUVAnalyser or YUVEditor, you need to load or save YUV files, and need to specify the right YUV format.
When you select a file to read or write, a YUV format selection dialog will pop up, to help you to pick up a right YUV format.
Writing a YUV file will be relatively easier than reading one. Since you can choose whatever format (as long as it is valid) format to write. On the other hand, to read a YUV file, you need to specify its data format: whether it is in 4:4:4, 4:2:2 or 4:2:0 sampling format, whether it has one single progressive frame or two interlaced fields, whether its pixel is packed or in planar format. If you do not know the format, this dialog will provide a help for you to guess one.
Whenever a format is selected, three pictures will be displayed. The first one is the preview image, which is a scaled image of the first YUV frame. If you see a right colorful and meaningful image, you have selected the right format. The second is the diagram illustration of the data structure, to help you understand the internal data organization inside the file. The third one is the data dump of the file, which is the data display byte by byte (scaled). It provides you a “global view” of the data inside the file, and can be useful for you to guess what’s the right format.
For example, when a YUV file is first loaded, the dialog display is shown as this:
(Click on above image to display a full resolution image)
From the “Binary Data Dump Out” picture, we can see that there is a “big” image component, followed by several “small” images. This suggests that the sampling format is not 4:4:4 nor 4:2:2, and U/V components are down-sampled. So, we should choose YUV 4:2:0 in Sampling format. Then we get the right YUV format::
(Click on above image to display a full resolution image)
The program will try to remember your last used format for all four format selections, this will make it easier and faster for you to load files every time with same formats.
Tricks:
For some of the format combination, there are associated FOURCC (www.fourcc.org) defined (not all formats). You can direct select format by FOURCC name, then other format settings will be set automatically to match that FOURCC.
Another useful feature is that the program will try to guess the format from the yuv file name, if the file name’s extension is FOURCC name. This way, when you load the file, the program will analyze the file name string and try to guess the format and resolution, then fill in the format selection automatically for you. You can use following name conventions to use this feature :
- The file extension use four letters instead of three, and the four letters are the names as defined by FOURCC, like:
- UYVY (YUV422, U-Y-V-Y, progressive, packed)
- UYNV (same as UYVY )
- Y422 (same as UYVY )
- IUYV ( YUV422, U-Y-V-Y, interlaced, packed)
- YUYV (YUV422, Y-U-Y-V, progressive, packed)
- YUNV (same as YUYV)
- V422 (same as YUYV)
- YUY2 (same as YUYV)
- YVYU (YUV422, Y-V-Y-U, progressive, packed)
- IYU2 ( YUV444, U-Y-V, progressive, packed)
- YV16 (YUV422, Y-U-V, progressive, planar)
- YV12 (YUV420, Y-V-U, progressive, planar)
- IYUV (YUV420, Y-U-V, progressive, planar)
- I420 (same as IYUV)
- For resolution, you have to give the width and height info in the name too, like: forman_352x288.yuyv. The width and height in the name must start with “_”, and then follows image width, then “x” or “X”, then image height, then “.” + four letters as file extension.
- The program only guesses if above conditions are satisfied. If not, no format information will be used, just same as *.yuv file.
The third trick: You can select more than one YUV files to play. In file selection window, holding CTRL key while clicking the mouse will allow you to select more than one file names, or by holding SHIFT key, to select all files between your first selected file name. All selected files will form a play list, and they will be played one by one. Please note, all the selected files have to be in the exact same format and resolution. The program only askes you once to select file format.