avcodec: Ignoring errors is only possible before the input end

Fixes: out of array read
Fixes: Ticket 10308

Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
(cherry picked from commit fead656a7b)
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>

libavcodec/h263dec.c

@@ -281,7 +281,7 @@ static int decode_slice(MpegEncContext *s)
                 ff_er_add_slice(&s->er, s->resync_mb_x, s->resync_mb_y,
                                 s->mb_x, s->mb_y, ER_MB_ERROR & part_mask);
 
-                if (s->avctx->err_recognition & AV_EF_IGNORE_ERR)
+                if ((s->avctx->err_recognition & AV_EF_IGNORE_ERR) && get_bits_left(&s->gb) > 0)
                     continue;
                 return AVERROR_INVALIDDATA;
             }

libavcodec/mpeg4videodec.c

@@ -1437,7 +1437,7 @@ static inline int mpeg4_decode_block(Mpeg4DecContext *ctx, int16_t *block,
                                 if (SHOW_UBITS(re, &s->gb, 1) == 0) {
                                     av_log(s->avctx, AV_LOG_ERROR,
                                            "1. marker bit missing in 3. esc\n");
-                                    if (!(s->avctx->err_recognition & AV_EF_IGNORE_ERR))
+                                    if (!(s->avctx->err_recognition & AV_EF_IGNORE_ERR) || get_bits_left(&s->gb) <= 0)
                                         return AVERROR_INVALIDDATA;
                                 }
                                 SKIP_CACHE(re, &s->gb, 1);
@@ -1448,7 +1448,7 @@ static inline int mpeg4_decode_block(Mpeg4DecContext *ctx, int16_t *block,
                                 if (SHOW_UBITS(re, &s->gb, 1) == 0) {
                                     av_log(s->avctx, AV_LOG_ERROR,
                                            "2. marker bit missing in 3. esc\n");
-                                    if (!(s->avctx->err_recognition & AV_EF_IGNORE_ERR))
+                                    if (!(s->avctx->err_recognition & AV_EF_IGNORE_ERR) || get_bits_left(&s->gb) <= 0)
                                         return AVERROR_INVALIDDATA;
                                 }