avcodec/mjpegdec: allow lowres with amv

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavcodec/mjpegdec.c

@@ -1112,11 +1112,6 @@ static int mjpeg_decode_scan(MJpegDecodeContext *s, int nb_components, int Ah,
     if (mb_bitmask)
         init_get_bits(&mb_bitmask_gb, mb_bitmask, s->mb_width * s->mb_height);
 
-    if (s->flipped && s->avctx->lowres) {
-        av_log(s->avctx, AV_LOG_ERROR, "Can not flip image with lowres\n");
-        s->flipped = 0;
-    }
-
     s->restart_count = 0;
 
     for (i = 0; i < nb_components; i++) {

libavcodec/sp5xdec.c

@@ -117,5 +117,6 @@ AVCodec ff_amv_decoder = {
     .init           = ff_mjpeg_decode_init,
     .close          = ff_mjpeg_decode_end,
     .decode         = sp5x_decode_frame,
+    .max_lowres     = 3,
 };
 #endif