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svq3: Use a separate buffer for decoding the slices

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The AVPacket.data should be considered read-only.
This commit is contained in:
Luca Barbato 2016-03-12 17:46:36 +01:00
parent 2f4a1bb9bf
commit 1098f5c049
1 changed files with 32 additions and 23 deletions
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55
libavcodec/svq3.c
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@ -75,10 +75,12 @@ typedef struct SVQ3Context {
H264Picture *cur_pic;
H264Picture *next_pic;
H264Picture *last_pic;
GetBitContext gb;
uint8_t *slice_buf;
int slice_size;
int halfpel_flag;
int thirdpel_flag;
int unknown_flag;
int next_slice_index;
uint32_t watermark_key;
int adaptive_quant;
int next_p_frame_damaged;
@ -780,37 +782,43 @@ static int svq3_decode_slice_header(AVCodecContext *avctx)
int i, header;
unsigned slice_id;
header = get_bits(&h->gb, 8);
header = get_bits(&s->gb, 8);
if (((header & 0x9F) != 1 && (header & 0x9F) != 2) || (header & 0x60) == 0) {
/* TODO: what? */
av_log(avctx, AV_LOG_ERROR, "unsupported slice header (%02X)\n", header);
return -1;
} else {
int slice_bits, slice_bytes, slice_length;
int length = header >> 5 & 3;
s->next_slice_index = get_bits_count(&h->gb) +
8 * show_bits(&h->gb, 8 * length) +
8 * length;
slice_length = show_bits(&s->gb, 8 * length);
slice_bits = slice_length * 8;
slice_bytes = slice_length + length - 1;
if (s->next_slice_index > h->gb.size_in_bits) {
if (slice_bytes > get_bits_left(&s->gb)) {
av_log(avctx, AV_LOG_ERROR, "slice after bitstream end\n");
return -1;
}
h->gb.size_in_bits = s->next_slice_index - 8 * (length - 1);
skip_bits(&h->gb, 8);
skip_bits(&s->gb, 8);
av_fast_malloc(&s->slice_buf, &s->slice_size, slice_bytes + AV_INPUT_BUFFER_PADDING_SIZE);
if (!s->slice_buf)
return AVERROR(ENOMEM);
memcpy(s->slice_buf, s->gb.buffer + s->gb.index / 8, slice_bytes);
init_get_bits(&h->gb, s->slice_buf, slice_bits);
if (s->watermark_key) {
uint32_t header = AV_RL32(&h->gb.buffer[(get_bits_count(&h->gb) >> 3) + 1]);
AV_WL32(&h->gb.buffer[(get_bits_count(&h->gb) >> 3) + 1],
header ^ s->watermark_key);
uint32_t header = AV_RL32(&h->gb.buffer[1]);
AV_WL32(&h->gb.buffer[1], header ^ s->watermark_key);
}
if (length > 0) {
memcpy((uint8_t *) &h->gb.buffer[get_bits_count(&h->gb) >> 3],
&h->gb.buffer[h->gb.size_in_bits >> 3], length - 1);
memcpy(s->slice_buf, &s->slice_buf[slice_length], length - 1);
}
skip_bits_long(&h->gb, 0);
skip_bits_long(&s->gb, slice_bytes * 8);
}
if ((slice_id = svq3_get_ue_golomb(&h->gb)) >= 3) {
@ -1153,7 +1161,9 @@ static int svq3_decode_frame(AVCodecContext *avctx, void *data,
return 0;
}
init_get_bits(&h->gb, buf, 8 * buf_size);
ret = init_get_bits(&s->gb, buf, 8 * buf_size);
if (ret < 0)
return ret;
sl->mb_x = sl->mb_y = sl->mb_xy = 0;
@ -1269,15 +1279,13 @@ static int svq3_decode_frame(AVCodecContext *avctx, void *data,
unsigned mb_type;
sl->mb_xy = sl->mb_x + sl->mb_y * h->mb_stride;
if ((get_bits_count(&h->gb) + 7) >= h->gb.size_in_bits &&
((get_bits_count(&h->gb) & 7) == 0 ||
show_bits(&h->gb, -get_bits_count(&h->gb) & 7) == 0)) {
skip_bits(&h->gb, s->next_slice_index - get_bits_count(&h->gb));
h->gb.size_in_bits = 8 * buf_size;
if (svq3_decode_slice_header(avctx))
return -1;
if ((get_bits_left(&h->gb)) <= 7) {
if (((get_bits_count(&h->gb) & 7) == 0 ||
show_bits(&h->gb, get_bits_left(&h->gb) & 7) == 0)) {
if (svq3_decode_slice_header(avctx))
return -1;
}
/* TODO: support s->mb_skip_run */
}
@ -1341,6 +1349,7 @@ static av_cold int svq3_decode_end(AVCodecContext *avctx)
av_freep(&s->cur_pic);
av_freep(&s->next_pic);
av_freep(&s->last_pic);
av_freep(&s->slice_buf);
memset(&h->cur_pic, 0, sizeof(h->cur_pic));