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Slightly simplify first part of ipvideo_decode_block_opcode_0xA, 

hopefully allows for further simplifications in the future.

Originally committed as revision 18280 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Reimar Döffinger 2009-03-31 18:48:31 +00:00
parent f938cbf984
commit 5e8b83ac3b
1 changed files with 15 additions and 22 deletions
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37
libavcodec/interplayvideo.c
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@ -399,12 +399,10 @@ static int ipvideo_decode_block_opcode_0x9(IpvideoContext *s)
static int ipvideo_decode_block_opcode_0xA(IpvideoContext *s)
{
int x, y;
unsigned char P[16];
unsigned char P[8];
unsigned char B[16];
int flags = 0;
int index;
int split;
int lower_half;
/* 4-color encoding for each 4x4 quadrant, or 4-color encoding on
* either top and bottom or left and right halves */
@ -417,28 +415,23 @@ static int ipvideo_decode_block_opcode_0xA(IpvideoContext *s)
/* 4-color encoding for each quadrant; need 28 more bytes */
CHECK_STREAM_PTR(28);
s->stream_ptr -= 4;
memcpy(B, s->stream_ptr, 4);
s->stream_ptr += 4;
for (y = 4; y < 16; y += 4) {
memcpy(P + y, s->stream_ptr, 4);
s->stream_ptr += 4;
memcpy(B + y, s->stream_ptr, 4);
s->stream_ptr += 4;
}
for (y = 0; y < 8; y++) {
lower_half = (y >= 4) ? 4 : 0;
flags = (B[y + 8] << 8) | B[y];
for (x = 0; x < 8; x++, flags >>= 2) {
split = (x >= 4) ? 8 : 0;
index = split + lower_half + (flags & 0x03);
*s->pixel_ptr++ = P[index];
for (y = 0; y < 16; y++) {
// new values for each 4x4 block
if (!(y & 3)) {
memcpy(P, s->stream_ptr, 4);
s->stream_ptr += 4;
flags = bytestream_get_le32(&s->stream_ptr);
}
s->pixel_ptr += s->line_inc;
for (x = 0; x < 4; x++, flags >>= 2) {
*s->pixel_ptr++ = P[flags & 0x03];
}
s->pixel_ptr += s->stride - 4;
// switch to right half
if (y == 7) s->pixel_ptr -= 8 * s->stride - 4;
}
} else {