ccp2_try_format
ccp2_try_format(ccp2, sd_state, fse->pad, &format, fse->which);
ccp2_try_format(ccp2, sd_state, fse->pad, &format, fse->which);
ccp2_try_format(ccp2, sd_state, fmt->pad, &fmt->format, fmt->which);
ccp2_try_format(ccp2, sd_state, CCP2_PAD_SOURCE, format,