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-rw-r--r--libavcodec/escape124.c123
1 files changed, 66 insertions, 57 deletions
diff --git a/libavcodec/escape124.c b/libavcodec/escape124.c
index 86a63a4..cffd3e1 100644
--- a/libavcodec/escape124.c
+++ b/libavcodec/escape124.c
@@ -2,26 +2,26 @@
* Escape 124 Video Decoder
* Copyright (C) 2008 Eli Friedman (eli.friedman@gmail.com)
*
- * This file is part of Libav.
+ * This file is part of FFmpeg.
*
- * Libav is free software; you can redistribute it and/or
+ * FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
- * Libav is distributed in the hope that it will be useful,
+ * FFmpeg is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
- * License along with Libav; if not, write to the Free Software
+ * License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#define BITSTREAM_READER_LE
#include "avcodec.h"
-#include "bitstream.h"
+#include "get_bits.h"
#include "internal.h"
typedef union MacroBlock {
@@ -48,11 +48,6 @@ typedef struct Escape124Context {
CodeBook codebooks[3];
} Escape124Context;
-static int can_safely_read(BitstreamContext *bc, int bits)
-{
- return bitstream_bits_left(bc) >= bits;
-}
-
/**
* Initialize the decoder
* @param avctx decoder context
@@ -80,20 +75,20 @@ static av_cold int escape124_decode_close(AVCodecContext *avctx)
Escape124Context *s = avctx->priv_data;
for (i = 0; i < 3; i++)
- av_free(s->codebooks[i].blocks);
+ av_freep(&s->codebooks[i].blocks);
av_frame_free(&s->frame);
return 0;
}
-static CodeBook unpack_codebook(BitstreamContext *bc, unsigned depth,
+static CodeBook unpack_codebook(GetBitContext* gb, unsigned depth,
unsigned size)
{
unsigned i, j;
CodeBook cb = { 0 };
- if (!can_safely_read(bc, size * 34))
+ if (size >= INT_MAX / 34 || get_bits_left(gb) < size * 34)
return cb;
if (size >= INT_MAX / sizeof(MacroBlock))
@@ -105,9 +100,9 @@ static CodeBook unpack_codebook(BitstreamContext *bc, unsigned depth,
cb.depth = depth;
cb.size = size;
for (i = 0; i < size; i++) {
- unsigned mask_bits = bitstream_read(bc, 4);
- unsigned color0 = bitstream_read(bc, 15);
- unsigned color1 = bitstream_read(bc, 15);
+ unsigned mask_bits = get_bits(gb, 4);
+ unsigned color0 = get_bits(gb, 15);
+ unsigned color1 = get_bits(gb, 15);
for (j = 0; j < 4; j++) {
if (mask_bits & (1 << j))
@@ -119,43 +114,47 @@ static CodeBook unpack_codebook(BitstreamContext *bc, unsigned depth,
return cb;
}
-static unsigned decode_skip_count(BitstreamContext *bc)
+static unsigned decode_skip_count(GetBitContext* gb)
{
unsigned value;
// This function reads a maximum of 23 bits,
// which is within the padding space
- if (!can_safely_read(bc, 1))
+ if (get_bits_left(gb) < 1)
return -1;
- value = bitstream_read_bit(bc);
+ value = get_bits1(gb);
if (!value)
return value;
- value += bitstream_read(bc, 3);
+ value += get_bits(gb, 3);
if (value != (1 + ((1 << 3) - 1)))
return value;
- value += bitstream_read(bc, 7);
+ value += get_bits(gb, 7);
if (value != (1 + ((1 << 3) - 1)) + ((1 << 7) - 1))
return value;
- return value + bitstream_read(bc, 12);
+ return value + get_bits(gb, 12);
}
-static MacroBlock decode_macroblock(Escape124Context *s, BitstreamContext *bc,
- int *codebook_index, int superblock_index)
+static MacroBlock decode_macroblock(Escape124Context* s, GetBitContext* gb,
+ int* codebook_index, int superblock_index)
{
// This function reads a maximum of 22 bits; the callers
// guard this function appropriately
unsigned block_index, depth;
- int value = bitstream_read_bit(bc);
+ int value = get_bits1(gb);
if (value) {
- static const char transitions[3][2] = { {2, 1}, {0, 2}, {1, 0} };
- value = bitstream_read_bit(bc);
+ static const int8_t transitions[3][2] = { {2, 1}, {0, 2}, {1, 0} };
+ value = get_bits1(gb);
*codebook_index = transitions[*codebook_index][value];
}
depth = s->codebooks[*codebook_index].depth;
- block_index = bitstream_read(bc, depth);
+
+ // depth = 0 means that this shouldn't read any bits;
+ // in theory, this is the same as get_bits(gb, 0), but
+ // that doesn't actually work.
+ block_index = get_bitsz(gb, depth);
if (*codebook_index == 1) {
block_index += superblock_index << s->codebooks[1].depth;
@@ -200,12 +199,11 @@ static int escape124_decode_frame(AVCodecContext *avctx,
void *data, int *got_frame,
AVPacket *avpkt)
{
- const uint8_t *buf = avpkt->data;
int buf_size = avpkt->size;
Escape124Context *s = avctx->priv_data;
AVFrame *frame = data;
- BitstreamContext bc;
+ GetBitContext gb;
unsigned frame_flags, frame_size;
unsigned i;
@@ -215,17 +213,23 @@ static int escape124_decode_frame(AVCodecContext *avctx,
uint16_t* old_frame_data, *new_frame_data;
unsigned old_stride, new_stride;
+
int ret;
- bitstream_init8(&bc, buf, buf_size);
+ if ((ret = init_get_bits8(&gb, avpkt->data, avpkt->size)) < 0)
+ return ret;
// This call also guards the potential depth reads for the
// codebook unpacking.
- if (!can_safely_read(&bc, 64))
+ // Check if the amount we will read minimally is available on input.
+ // The 64 represent the immediately next 2 frame_* elements read, the 23/4320
+ // represent a lower bound of the space needed for skipped superblocks. Non
+ // skipped SBs need more space.
+ if (get_bits_left(&gb) < 64 + s->num_superblocks * 23LL / 4320)
return -1;
- frame_flags = bitstream_read(&bc, 32);
- frame_size = bitstream_read(&bc, 32);
+ frame_flags = get_bits_long(&gb, 32);
+ frame_size = get_bits_long(&gb, 32);
// Leave last frame unchanged
// FIXME: Is this necessary? I haven't seen it in any real samples
@@ -233,7 +237,7 @@ static int escape124_decode_frame(AVCodecContext *avctx,
if (!s->frame->data[0])
return AVERROR_INVALIDDATA;
- av_log(NULL, AV_LOG_DEBUG, "Skipping frame\n");
+ av_log(avctx, AV_LOG_DEBUG, "Skipping frame\n");
*got_frame = 1;
if ((ret = av_frame_ref(frame, s->frame)) < 0)
@@ -248,10 +252,14 @@ static int escape124_decode_frame(AVCodecContext *avctx,
if (i == 2) {
// This codebook can be cut off at places other than
// powers of 2, leaving some of the entries undefined.
- cb_size = bitstream_read(&bc, 20);
+ cb_size = get_bits_long(&gb, 20);
+ if (!cb_size) {
+ av_log(avctx, AV_LOG_ERROR, "Invalid codebook size 0.\n");
+ return AVERROR_INVALIDDATA;
+ }
cb_depth = av_log2(cb_size - 1) + 1;
} else {
- cb_depth = bitstream_read(&bc, 4);
+ cb_depth = get_bits(&gb, 4);
if (i == 0) {
// This is the most basic codebook: pow(2,depth) entries
// for a depth-length key
@@ -263,17 +271,20 @@ static int escape124_decode_frame(AVCodecContext *avctx,
cb_size = s->num_superblocks << cb_depth;
}
}
- av_free(s->codebooks[i].blocks);
- s->codebooks[i] = unpack_codebook(&bc, cb_depth, cb_size);
+ if (s->num_superblocks >= INT_MAX >> cb_depth) {
+ av_log(avctx, AV_LOG_ERROR, "Depth or num_superblocks are too large\n");
+ return AVERROR_INVALIDDATA;
+ }
+
+ av_freep(&s->codebooks[i].blocks);
+ s->codebooks[i] = unpack_codebook(&gb, cb_depth, cb_size);
if (!s->codebooks[i].blocks)
return -1;
}
}
- if ((ret = ff_get_buffer(avctx, frame, AV_GET_BUFFER_FLAG_REF)) < 0) {
- av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
+ if ((ret = ff_get_buffer(avctx, frame, AV_GET_BUFFER_FLAG_REF)) < 0)
return ret;
- }
new_frame_data = (uint16_t*)frame->data[0];
new_stride = frame->linesize[0] / 2;
@@ -289,7 +300,7 @@ static int escape124_decode_frame(AVCodecContext *avctx,
if (skip == -1) {
// Note that this call will make us skip the rest of the blocks
// if the frame prematurely ends
- skip = decode_skip_count(&bc);
+ skip = decode_skip_count(&gb);
}
if (skip) {
@@ -299,10 +310,10 @@ static int escape124_decode_frame(AVCodecContext *avctx,
copy_superblock(sb.pixels, 8,
old_frame_data, old_stride);
- while (can_safely_read(&bc, 1) && !bitstream_read_bit(&bc)) {
+ while (get_bits_left(&gb) >= 1 && !get_bits1(&gb)) {
unsigned mask;
- mb = decode_macroblock(s, &bc, &cb_index, superblock_index);
- mask = bitstream_read(&bc, 16);
+ mb = decode_macroblock(s, &gb, &cb_index, superblock_index);
+ mask = get_bits(&gb, 16);
multi_mask |= mask;
for (i = 0; i < 16; i++) {
if (mask & mask_matrix[i]) {
@@ -311,29 +322,27 @@ static int escape124_decode_frame(AVCodecContext *avctx,
}
}
- if (can_safely_read(&bc, 1) && !bitstream_read_bit(&bc)) {
- unsigned inv_mask = bitstream_read(&bc, 4);
+ if (!get_bits1(&gb)) {
+ unsigned inv_mask = get_bits(&gb, 4);
for (i = 0; i < 4; i++) {
if (inv_mask & (1 << i)) {
multi_mask ^= 0xF << i*4;
} else {
- multi_mask ^= bitstream_read(&bc, 4) << i * 4;
+ multi_mask ^= get_bits(&gb, 4) << i*4;
}
}
for (i = 0; i < 16; i++) {
if (multi_mask & mask_matrix[i]) {
- if (!can_safely_read(&bc, 1))
- break;
- mb = decode_macroblock(s, &bc, &cb_index,
+ mb = decode_macroblock(s, &gb, &cb_index,
superblock_index);
insert_mb_into_sb(&sb, mb, i);
}
}
} else if (frame_flags & (1 << 16)) {
- while (can_safely_read(&bc, 1) && !bitstream_read_bit(&bc)) {
- mb = decode_macroblock(s, &bc, &cb_index, superblock_index);
- insert_mb_into_sb(&sb, mb, bitstream_read(&bc, 4));
+ while (get_bits_left(&gb) >= 1 && !get_bits1(&gb)) {
+ mb = decode_macroblock(s, &gb, &cb_index, superblock_index);
+ insert_mb_into_sb(&sb, mb, get_bits(&gb, 4));
}
}
@@ -353,9 +362,9 @@ static int escape124_decode_frame(AVCodecContext *avctx,
skip--;
}
- av_log(NULL, AV_LOG_DEBUG,
+ av_log(avctx, AV_LOG_DEBUG,
"Escape sizes: %i, %i, %i\n",
- frame_size, buf_size, bitstream_tell(&bc) / 8);
+ frame_size, buf_size, get_bits_count(&gb) / 8);
av_frame_unref(s->frame);
if ((ret = av_frame_ref(s->frame, frame)) < 0)
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