indeo4: Do not access missing reference MV

Reported-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
CC: libav-stable@libav.org
This commit is contained in:
Luca Barbato 2013-07-12 14:32:03 +02:00
parent 031be5b41b
commit 8435bca087
1 changed files with 14 additions and 10 deletions

View File

@ -459,7 +459,7 @@ static int decode_mb_info(IVI45DecContext *ctx, IVIBandDesc *band,
}
mb->mv_x = mb->mv_y = 0; /* no motion vector coded */
if (band->inherit_mv) {
if (band->inherit_mv && ref_mb) {
/* motion vector inheritance */
if (mv_scale) {
mb->mv_x = ivi_scale_mv(ref_mb->mv_x, mv_scale);
@ -471,7 +471,10 @@ static int decode_mb_info(IVI45DecContext *ctx, IVIBandDesc *band,
}
} else {
if (band->inherit_mv) {
mb->type = ref_mb->type; /* copy mb_type from corresponding reference mb */
/* copy mb_type from corresponding reference mb */
if (!ref_mb)
return AVERROR_INVALIDDATA;
mb->type = ref_mb->type;
} else if (ctx->frame_type == FRAMETYPE_INTRA ||
ctx->frame_type == FRAMETYPE_INTRA1) {
mb->type = 0; /* mb_type is always INTRA for intra-frames */
@ -495,14 +498,15 @@ static int decode_mb_info(IVI45DecContext *ctx, IVIBandDesc *band,
mb->mv_x = mb->mv_y = 0; /* there is no motion vector in intra-macroblocks */
} else {
if (band->inherit_mv) {
/* motion vector inheritance */
if (mv_scale) {
mb->mv_x = ivi_scale_mv(ref_mb->mv_x, mv_scale);
mb->mv_y = ivi_scale_mv(ref_mb->mv_y, mv_scale);
} else {
mb->mv_x = ref_mb->mv_x;
mb->mv_y = ref_mb->mv_y;
}
if (ref_mb)
/* motion vector inheritance */
if (mv_scale) {
mb->mv_x = ivi_scale_mv(ref_mb->mv_x, mv_scale);
mb->mv_y = ivi_scale_mv(ref_mb->mv_y, mv_scale);
} else {
mb->mv_x = ref_mb->mv_x;
mb->mv_y = ref_mb->mv_y;
}
} else {
/* decode motion vector deltas */
mv_delta = get_vlc2(&ctx->gb, ctx->mb_vlc.tab->table,