* [FFmpeg-devel] [PATCH] avcodec/mpegvideo_dec: Avoid implicit NULL + offset
@ 2025-07-03 20:52 Andreas Rheinhardt
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From: Andreas Rheinhardt @ 2025-07-03 20:52 UTC (permalink / raw)
To: FFmpeg development discussions and patches
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Patch attached.
- Andreas
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From 1f85427ebe8ac63ba0d89c49bc0df917106753cb Mon Sep 17 00:00:00 2001
From: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
Date: Thu, 3 Jul 2025 22:32:15 +0200
Subject: [PATCH] avcodec/mpegvideo_dec: Avoid implicit NULL + offset
Happens since 4fc874ef0813d39983f9b634cec42798aa94b57a
when this code is called via error resilience.
Also do the same for wmv2dec.c.
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
---
libavcodec/mpegvideo_dec.c | 50 +++++++++++++++++++-------------------
libavcodec/wmv2dec.c | 15 ++++++------
2 files changed, 33 insertions(+), 32 deletions(-)
diff --git a/libavcodec/mpegvideo_dec.c b/libavcodec/mpegvideo_dec.c
index e9d0009f3c..4a54f6cd61 100644
--- a/libavcodec/mpegvideo_dec.c
+++ b/libavcodec/mpegvideo_dec.c
@@ -851,10 +851,10 @@ unhandled:
/* add block[] to dest[] */
static inline void add_dct(MpegEncContext *s,
- int16_t *block, int i, uint8_t *dest, int line_size)
+ int16_t block[][64], int i, uint8_t *dest, int line_size)
{
if (s->block_last_index[i] >= 0) {
- s->idsp.idct_add(dest, line_size, block);
+ s->idsp.idct_add(dest, line_size, block[i]);
}
}
@@ -867,12 +867,12 @@ static inline void put_dct(MpegEncContext *s,
}
static inline void add_dequant_dct(MpegEncContext *s,
- int16_t *block, int i, uint8_t *dest, int line_size, int qscale)
+ int16_t block[][64], int i, uint8_t *dest, int line_size, int qscale)
{
if (s->block_last_index[i] >= 0) {
- s->dct_unquantize_inter(s, block, i, qscale);
+ s->dct_unquantize_inter(s, block[i], i, qscale);
- s->idsp.idct_add(dest, line_size, block);
+ s->idsp.idct_add(dest, line_size, block[i]);
}
}
@@ -959,44 +959,44 @@ void mpv_reconstruct_mb_internal(MpegEncContext *s, int16_t block[12][64],
/* add dct residue */
if (is_mpeg12 != DEFINITELY_MPEG12_H261 && s->dct_unquantize_inter) {
// H.263, H.263+, H.263I, FLV, RV10, RV20 and MPEG-4 with MPEG-2 quantization
- add_dequant_dct(s, block[0], 0, dest_y , dct_linesize, s->qscale);
- add_dequant_dct(s, block[1], 1, dest_y + block_size, dct_linesize, s->qscale);
- add_dequant_dct(s, block[2], 2, dest_y + dct_offset , dct_linesize, s->qscale);
- add_dequant_dct(s, block[3], 3, dest_y + dct_offset + block_size, dct_linesize, s->qscale);
+ add_dequant_dct(s, block, 0, dest_y , dct_linesize, s->qscale);
+ add_dequant_dct(s, block, 1, dest_y + block_size, dct_linesize, s->qscale);
+ add_dequant_dct(s, block, 2, dest_y + dct_offset , dct_linesize, s->qscale);
+ add_dequant_dct(s, block, 3, dest_y + dct_offset + block_size, dct_linesize, s->qscale);
if (!CONFIG_GRAY || !(s->avctx->flags & AV_CODEC_FLAG_GRAY)) {
av_assert2(s->chroma_y_shift);
- add_dequant_dct(s, block[4], 4, dest_cb, uvlinesize, s->chroma_qscale);
- add_dequant_dct(s, block[5], 5, dest_cr, uvlinesize, s->chroma_qscale);
+ add_dequant_dct(s, block, 4, dest_cb, uvlinesize, s->chroma_qscale);
+ add_dequant_dct(s, block, 5, dest_cr, uvlinesize, s->chroma_qscale);
}
} else if (is_mpeg12 == DEFINITELY_MPEG12_H261 || lowres_flag || (s->codec_id != AV_CODEC_ID_WMV2)) {
// H.261, MPEG-1, MPEG-2, MPEG-4 with H.263 quantization,
// MSMP4V1-3 and WMV1.
// Also RV30, RV40 and the VC-1 family when performing error resilience,
// but all blocks are skipped in this case.
- add_dct(s, block[0], 0, dest_y , dct_linesize);
- add_dct(s, block[1], 1, dest_y + block_size, dct_linesize);
- add_dct(s, block[2], 2, dest_y + dct_offset , dct_linesize);
- add_dct(s, block[3], 3, dest_y + dct_offset + block_size, dct_linesize);
+ add_dct(s, block, 0, dest_y , dct_linesize);
+ add_dct(s, block, 1, dest_y + block_size, dct_linesize);
+ add_dct(s, block, 2, dest_y + dct_offset , dct_linesize);
+ add_dct(s, block, 3, dest_y + dct_offset + block_size, dct_linesize);
if (!CONFIG_GRAY || !(s->avctx->flags & AV_CODEC_FLAG_GRAY)) {
if (s->chroma_y_shift) {//Chroma420
- add_dct(s, block[4], 4, dest_cb, uvlinesize);
- add_dct(s, block[5], 5, dest_cr, uvlinesize);
+ add_dct(s, block, 4, dest_cb, uvlinesize);
+ add_dct(s, block, 5, dest_cr, uvlinesize);
} else {
//chroma422
dct_linesize = uvlinesize << s->interlaced_dct;
dct_offset = s->interlaced_dct ? uvlinesize : uvlinesize*block_size;
- add_dct(s, block[4], 4, dest_cb, dct_linesize);
- add_dct(s, block[5], 5, dest_cr, dct_linesize);
- add_dct(s, block[6], 6, dest_cb + dct_offset, dct_linesize);
- add_dct(s, block[7], 7, dest_cr + dct_offset, dct_linesize);
+ add_dct(s, block, 4, dest_cb, dct_linesize);
+ add_dct(s, block, 5, dest_cr, dct_linesize);
+ add_dct(s, block, 6, dest_cb + dct_offset, dct_linesize);
+ add_dct(s, block, 7, dest_cr + dct_offset, dct_linesize);
if (!s->chroma_x_shift) {//Chroma444
- add_dct(s, block[8], 8, dest_cb + block_size, dct_linesize);
- add_dct(s, block[9], 9, dest_cr + block_size, dct_linesize);
- add_dct(s, block[10], 10, dest_cb + block_size + dct_offset, dct_linesize);
- add_dct(s, block[11], 11, dest_cr + block_size + dct_offset, dct_linesize);
+ add_dct(s, block, 8, dest_cb + block_size, dct_linesize);
+ add_dct(s, block, 9, dest_cr + block_size, dct_linesize);
+ add_dct(s, block, 10, dest_cb + block_size + dct_offset, dct_linesize);
+ add_dct(s, block, 11, dest_cr + block_size + dct_offset, dct_linesize);
}
}
} //fi gray
diff --git a/libavcodec/wmv2dec.c b/libavcodec/wmv2dec.c
index 082ebf7a84..512d63b23e 100644
--- a/libavcodec/wmv2dec.c
+++ b/libavcodec/wmv2dec.c
@@ -56,12 +56,13 @@ typedef struct WMV2DecContext {
DECLARE_ALIGNED(32, int16_t, abt_block2)[6][64];
} WMV2DecContext;
-static void wmv2_add_block(WMV2DecContext *w, int16_t *block1,
+static void wmv2_add_block(WMV2DecContext *w, int16_t blocks1[][64],
uint8_t *dst, int stride, int n)
{
H263DecContext *const h = &w->ms.h;
if (h->c.block_last_index[n] >= 0) {
+ int16_t *block1 = blocks1[n];
switch (w->abt_type_table[n]) {
case 0:
w->common.wdsp.idct_add(dst, stride, block1);
@@ -87,16 +88,16 @@ void ff_wmv2_add_mb(MpegEncContext *s, int16_t block1[6][64],
{
WMV2DecContext *const w = (WMV2DecContext *) s;
- wmv2_add_block(w, block1[0], dest_y, s->linesize, 0);
- wmv2_add_block(w, block1[1], dest_y + 8, s->linesize, 1);
- wmv2_add_block(w, block1[2], dest_y + 8 * s->linesize, s->linesize, 2);
- wmv2_add_block(w, block1[3], dest_y + 8 + 8 * s->linesize, s->linesize, 3);
+ wmv2_add_block(w, block1, dest_y, s->linesize, 0);
+ wmv2_add_block(w, block1, dest_y + 8, s->linesize, 1);
+ wmv2_add_block(w, block1, dest_y + 8 * s->linesize, s->linesize, 2);
+ wmv2_add_block(w, block1, dest_y + 8 + 8 * s->linesize, s->linesize, 3);
if (s->avctx->flags & AV_CODEC_FLAG_GRAY)
return;
- wmv2_add_block(w, block1[4], dest_cb, s->uvlinesize, 4);
- wmv2_add_block(w, block1[5], dest_cr, s->uvlinesize, 5);
+ wmv2_add_block(w, block1, dest_cb, s->uvlinesize, 4);
+ wmv2_add_block(w, block1, dest_cr, s->uvlinesize, 5);
}
static int parse_mb_skip(WMV2DecContext *w)
--
2.45.2
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