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svq3 watermark decoding support, based on reverse engineering work by chrono 

Originally committed as revision 15718 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Baptiste Coudurier 2008-10-26 23:34:44 +00:00
parent 65f65c3021
commit 1e002b602f
1 changed files with 36 additions and 0 deletions
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36
libavcodec/svq3.c
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@ -703,6 +703,10 @@ static int svq3_decode_slice_header (H264Context *h) {
s->gb.size_in_bits = h->next_slice_index - 8*(length - 1);
skip_bits(&s->gb, 8);
if (h->svq3_watermark_key) {
uint32_t header = AV_RL32(&s->gb.buffer[(get_bits_count(&s->gb)>>3)+1]);
AV_WL32(&s->gb.buffer[(get_bits_count(&s->gb)>>3)+1], header ^ h->svq3_watermark_key);
}
if (length > 0) {
memcpy ((uint8_t *) &s->gb.buffer[get_bits_count(&s->gb) >> 3],
&s->gb.buffer[s->gb.size_in_bits >> 3], (length - 1));
@ -828,6 +832,38 @@ static int svq3_decode_frame (AVCodecContext *avctx,
h->unknown_svq3_flag = get_bits1 (&gb);
avctx->has_b_frames = !s->low_delay;
if (h->unknown_svq3_flag) {
#ifdef CONFIG_ZLIB
unsigned watermark_width = svq3_get_ue_golomb(&gb);
unsigned watermark_height = svq3_get_ue_golomb(&gb);
int u1 = svq3_get_ue_golomb(&gb);
int u2 = get_bits(&gb, 8);
int u3 = get_bits(&gb, 2);
int u4 = svq3_get_ue_golomb(&gb);
unsigned buf_len = watermark_width*watermark_height*4;
int offset = (get_bits_count(&gb)+7)>>3;
uint8_t *buf;
if ((uint64_t)watermark_width*4 > UINT_MAX/watermark_height)
return -1;
buf = av_malloc(buf_len);
av_log(avctx, AV_LOG_DEBUG, "watermark size: %dx%d\n", watermark_width, watermark_height);
av_log(avctx, AV_LOG_DEBUG, "u1: %x u2: %x u3: %x compressed data size: %d offset: %d\n", u1, u2, u3, u4, offset);
if (uncompress(buf, (uLong*)&buf_len, extradata + 8 + offset, size - offset) != Z_OK) {
av_log(avctx, AV_LOG_ERROR, "could not uncompress watermark logo\n");
av_free(buf);
return -1;
}
h->svq3_watermark_key = ff_svq1_packet_checksum(buf, buf_len, 0);
h->svq3_watermark_key = h->svq3_watermark_key << 16 | h->svq3_watermark_key;
av_log(avctx, AV_LOG_DEBUG, "watermark key %#x\n", h->svq3_watermark_key);
av_free(buf);
#else
av_log(avctx, AV_LOG_ERROR, "this svq3 file contains watermark which need zlib support compiled in\n");
return -1;
#endif
}
}
}