We have videos in row format (.mov) that are 4:3 (768x576) and 5:4 (720x576). We have a recommended preset for streaming over DASH to HTML5 and Silverlight players (this is the second pass):
ffmpeg -i input.mp4 -an -vcodec libx264 -profile:v main -pass 2 \ -vf scale=320:180 -pix_fmt yuv420p -g 75 -keyint_min 25 -b:v 384k \ -maxrate 384k -bufsize 384k -passlogfile passlogfile_fp output_320x180_384.mp4
with 5 more, but different resolution and bitrate:
- 480:270 -b:v 700k
- 800:450 -b:v 1300k
- 960:540 -b:v 1300k
- 1280:720 -b:v 3500k
- 1920:1080 -b:v 5000k
With the 4:3 source videos we are happy with the result - the image doesn't get stretched, but players add black border to fit the width. Although we are not sure if this preset is suitable for these source videos.
With the 5:4 we are not really happy, because the image is stretched for 16:9 display. How can we achieve the same effect as with the 4:3 source videos? Are these presets suitable at all for these video formats or should we be looking for something else?
Appreciate your help. Our knowledge about encoding is pretty limited.