the encoded frame size of a standard SVCD is 480x480. Legal sizes for DVDs are 720x480, 704x480, 352x480 MPEG-2, and 352x240 MPEG-1
I'd recommend scaling down from 480x480 to 352x480 rather than up to 704x480.
I think I got it right - SVCDs have a SAR of 15:11 but the 1/2 DVD size would have a SAR of 20:11.
Going from SVCD to CVD/Half-D1 is like going from DV to CVD/Half-D1 (VCD is similar horizontally).
<http://www.iki.fi/znark/video/conversion/>
For example:
PAL SVCD source to CVD/Half-D1 target:
PAL_SVCD_sampling_matrix (width x height) = 480x576 PAL_SVCD_actual_active_picture_size = 468x576 PAL_SVCD_pixel_aspect_ratio = (4:3):(468:576) = 128:78
PAL_CVD_sampling_matrix (width x height) = 352x576 PAL_CVD_actual_active_picture_size = 351x576 PAL_CVD_aspect_ratio = (4:3):(351:576) = 256:117
vertical_conversion_factor = target_active_picture_height : source_active_picture_height = 576:576 = 1
horizontal_conversion_factor = (source_aspect_ratio) : (destination_aspect_ratio) x vertical_conversion_factor = (128:78) : (256:117) x 1 = 3:4
target_sampling_matrix_width = horizontal_conversion_factor x source_sampling_matrix_width = (3:4) x 480 = 360
target_sampling_matrix_height = vertical_conversion_factor x source_sampling_matrix_height = 1 x 576
The source image must be resampled to 360x576. However, the original target resolution was 352x576. Now we need to crop the 360x576 image with 4 pixels from both sides so that the frame width will become 352 pixels (frame height stays at 576 pixels).
--
NTSC SVCD source to CVD/Half-D1 target:
NTSC_SVCD_sampling_matrix (width x height) = 480x480 NTSC_SVCD_actual_active_picture_size = 474x486 NTSC_SVCD_pixel_aspect_ratio = (4:3):(474:486) = 108:79
NTSC_CVD_sampling_matrix (width x height) = 352x480 NTSC_CVD_actual_active_picture_size = 355.5x486 NTSC_CVD_aspect_ratio = (4:3):(355.5:486) = 144:79
vertical_conversion_factor = target_active_picture_height : source_active_picture_height = 486:486 = 1:1
horizontal_conversion_factor = (source_aspect_ratio) : (destination_aspect_ratio) x vertical_conversion_factor = (108:79) : (144:79) x 1 = 3:4
target_sampling_matrix_width = horizontal_conversion_factor x source_sampling_matrix_width = (3:4) x 480 = 360
target_sampling_matrix_height = vertical_conversion_factor x source_sampling_matrix_height = (1:1) x 480 = 480
The source image must be resampled to 360x480. However, the original target resolution was 352x480. Now we need to crop the 360x480 image with 4 pixels from both sides so that the frame width will become 352 pixels (frame height stays at 480 pixels).
-- Matti Haveri <[EMAIL PROTECTED]> <http://www.sjoki.uta.fi/~shmhav/>
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