resizing single frames in an mpeg

[bones9]

Hello to everybody!

I have an MPEG-2 video that contains some frames with a resolution of 720x480, while most are in 720x576 (all with 4:3 aspect ratio). Is there any way to resize these frames and make them also 720x576? I tried mencoder (in linux) and its scale filter but that didn't work.

Thank you in advance

[guns1inger]

Are these 720 x 480 visible within a 720 x 576 frame size, or actually 720 x 480 ? If so, how did they get into the stream ?

I would suggest the best bet is to use virtualdub-mpeg2 to split the clip at the start and end points of the reduced framesize section, then frameserve the small section to an encoder after resizing in virtualdub-mpeg. Finally, use the append function in virtualdub-mpeg2 to put it all back toether again.

[roxas]

Are you sure the smaller images are 720x480? MEncoder's scale filter should be fairly fine for the job but yea, you'd need to know the specifics about the vid. -ss(where it starts) and -endpos(length of vid that it shows) should help you if you only need certain parts scaled. The following are based on if the 720x480 images are centered perfectly:
stretching 480 to 576, does not keep image ratio.
-vf scale=720:692,crop=720:576:0:116
stretching original 480 image past video res, keeping 480 image ratio but losing part of the picture on the left and right
-vf crop=720:480:0:88,scale=864:576,crop=720:576
You can try these in MPlayer to see for yourself.