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mpeg12dec: move checks out of decode picture coding extension. 

Fixes out of array reads
Fixes Ticket1330

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
This commit is contained in:
Michael Niedermayer 2012-08-07 17:59:19 +02:00
parent 7febc5aa93
commit 2f6f2f4f73
1 changed files with 26 additions and 22 deletions
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48
libavcodec/mpeg12.c
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@ -1552,28 +1552,6 @@ static void mpeg_decode_picture_coding_extension(Mpeg1Context *s1)
s->chroma_420_type = get_bits1(&s->gb);
s->progressive_frame = get_bits1(&s->gb);
if (s->progressive_sequence && !s->progressive_frame) {
s->progressive_frame = 1;
av_log(s->avctx, AV_LOG_ERROR, "interlaced frame in progressive sequence, ignoring\n");
}
if (s->picture_structure == 0 || (s->progressive_frame && s->picture_structure != PICT_FRAME)) {
av_log(s->avctx, AV_LOG_ERROR, "picture_structure %d invalid, ignoring\n", s->picture_structure);
s->picture_structure = PICT_FRAME;
}
if (s->progressive_sequence && !s->frame_pred_frame_dct) {
av_log(s->avctx, AV_LOG_WARNING, "invalid frame_pred_frame_dct\n");
}
if (s->picture_structure == PICT_FRAME) {
s->first_field = 0;
s->v_edge_pos = 16 * s->mb_height;
} else {
s->first_field ^= 1;
s->v_edge_pos = 8 * s->mb_height;
memset(s->mbskip_table, 0, s->mb_stride * s->mb_height);
}
if (s->alternate_scan) {
ff_init_scantable(s->dsp.idct_permutation, &s->inter_scantable, ff_alternate_vertical_scan);
@ -2443,6 +2421,32 @@ static int decode_chunks(AVCodecContext *avctx,
}
break;
default:
if (start_code >= SLICE_MIN_START_CODE &&
start_code <= SLICE_MAX_START_CODE && last_code == PICTURE_START_CODE) {
if (s2->progressive_sequence && !s2->progressive_frame) {
s2->progressive_frame = 1;
av_log(s2->avctx, AV_LOG_ERROR, "interlaced frame in progressive sequence, ignoring\n");
}
if (s2->picture_structure == 0 || (s2->progressive_frame && s2->picture_structure != PICT_FRAME)) {
av_log(s2->avctx, AV_LOG_ERROR, "picture_structure %d invalid, ignoring\n", s2->picture_structure);
s2->picture_structure = PICT_FRAME;
}
if (s2->progressive_sequence && !s2->frame_pred_frame_dct) {
av_log(s2->avctx, AV_LOG_WARNING, "invalid frame_pred_frame_dct\n");
}
if (s2->picture_structure == PICT_FRAME) {
s2->first_field = 0;
s2->v_edge_pos = 16 * s2->mb_height;
} else {
s2->first_field ^= 1;
s2->v_edge_pos = 8 * s2->mb_height;
memset(s2->mbskip_table, 0, s2->mb_stride * s2->mb_height);
}
}
if (start_code >= SLICE_MIN_START_CODE &&
start_code <= SLICE_MAX_START_CODE && last_code != 0) {
const int field_pic = s2->picture_structure != PICT_FRAME;