Here are some more links with information of Aspect Ratio and FFmpeg resizing and filters.
I have then placed these settings into the resulting filename to help me identify what my new avi is set at. I could have set the original scale to 720:480 but, to highlight some of the various options, I have chosen ‘ih*2’ instead of the number ih*2 stands for Input Height x 2. Inside the quotations is the scale filter, followed by the aspect ratio filter. The above ffmpeg command has a filter chain which is identified by the -vf command. This information would be validated against other software if required.įor the purpose of this example, lets suggest that we just require to get this into a working standard, for demonstrative and presentation purposes only, and we have identified that it should be set to a display aspect ratio of 4:3.įfmpeg -i Test.mp4 -vf “scale=720:ih*2,setdar=4:3” -c:v rawvideo -f avi Test-UC-Resized-720×480.avi The actual image, without any aspect ratio correction would look like this… squished!įirst off, in order to make decisions based on the data, it would be beneficial to get as much information from the video stream as possible. So, we have a video frame of 720×240 but its being resized automatically by the player. SMplayer retains the horizontal measurements and resizes the vertical. It is always a bit hit and miss on how the player deals with the resizing. Have a read through this to read more on a few other examples! DAR refers to the viewable image dimensions, PAR refers to the physical dimensions of each pixel, and SAR refers to the number of horizontal versus vertical pixels. With digital, several types of aspect ratios exist: the display aspect ratio (DAR), the pixel aspect ratio (PAR) and the storage or sample aspect ratio (SAR).
Here I have a piece of H264 Video playing in FFplay, I can see from the FFmpeg console that it has a 720×240 pixel size but with a SAR of 1:2 which results on a DAR of 3:2.
FFplay retains the vertical size but reduces the horizontal by half
0 kommentar(er)
