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4bpp support

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Originally committed as revision 2487 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Roberto Togni 2003-11-09 21:54:49 +00:00
parent 1dc1ed9933
commit aa39a62205
1 changed files with 106 additions and 1 deletions
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105
libavcodec/msrle.c
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@ -56,6 +56,101 @@ typedef struct MsrleContext {
} \
stream_byte = s->buf[stream_ptr++];
static void msrle_decode_pal4(MsrleContext *s)
{
int stream_ptr = 0;
unsigned char rle_code;
unsigned char extra_byte, odd_pixel;
unsigned char stream_byte;
int pixel_ptr = 0;
int row_dec = s->frame.linesize[0];
int row_ptr = (s->avctx->height - 1) * row_dec;
int frame_size = row_dec * s->avctx->height;
int i;
/* make the palette available */
memcpy(s->frame.data[1], s->avctx->palctrl->palette, AVPALETTE_SIZE);
if (s->avctx->palctrl->palette_changed) {
s->frame.palette_has_changed = 1;
s->avctx->palctrl->palette_changed = 0;
}
while (row_ptr >= 0) {
FETCH_NEXT_STREAM_BYTE();
rle_code = stream_byte;
if (rle_code == 0) {
/* fetch the next byte to see how to handle escape code */
FETCH_NEXT_STREAM_BYTE();
if (stream_byte == 0) {
/* line is done, goto the next one */
row_ptr -= row_dec;
pixel_ptr = 0;
} else if (stream_byte == 1) {
/* decode is done */
return;
} else if (stream_byte == 2) {
/* reposition frame decode coordinates */
FETCH_NEXT_STREAM_BYTE();
pixel_ptr += stream_byte;
FETCH_NEXT_STREAM_BYTE();
row_ptr -= stream_byte * row_dec;
} else {
// copy pixels from encoded stream
odd_pixel = stream_byte & 1;
rle_code = (stream_byte + 1) / 2;
extra_byte = rle_code & 0x01;
if ((row_ptr + pixel_ptr + stream_byte > frame_size) ||
(row_ptr < 0)) {
av_log(s->avctx, AV_LOG_ERROR, " MS RLE: frame ptr just went out of bounds (1)\n");
return;
}
for (i = 0; i < rle_code; i++) {
if (pixel_ptr >= s->avctx->width)
break;
FETCH_NEXT_STREAM_BYTE();
s->frame.data[0][row_ptr + pixel_ptr] = stream_byte >> 4;
pixel_ptr++;
if (i + 1 == rle_code && odd_pixel)
break;
if (pixel_ptr >= s->avctx->width)
break;
s->frame.data[0][row_ptr + pixel_ptr] = stream_byte & 0x0F;
pixel_ptr++;
}
// if the RLE code is odd, skip a byte in the stream
if (extra_byte)
stream_ptr++;
}
} else {
// decode a run of data
if ((row_ptr + pixel_ptr + stream_byte > frame_size) ||
(row_ptr < 0)) {
av_log(s->avctx, AV_LOG_ERROR, " MS RLE: frame ptr just went out of bounds (1)\n");
return;
}
FETCH_NEXT_STREAM_BYTE();
for (i = 0; i < rle_code; i++) {
if (pixel_ptr >= s->avctx->width)
break;
if ((i & 1) == 0)
s->frame.data[0][row_ptr + pixel_ptr] = stream_byte >> 4;
else
s->frame.data[0][row_ptr + pixel_ptr] = stream_byte & 0x0F;
pixel_ptr++;
}
}
}
/* one last sanity check on the way out */
if (stream_ptr < s->size)
av_log(s->avctx, AV_LOG_ERROR, " MS RLE: ended frame decode with bytes left over (%d < %d)\n",
stream_ptr, s->size);
}
static void msrle_decode_pal8(MsrleContext *s)
{
int stream_ptr = 0;
@ -188,7 +283,17 @@ static int msrle_decode_frame(AVCodecContext *avctx,
memcpy(s->frame.data[0], s->prev_frame.data[0],
s->frame.linesize[0] * s->avctx->height);
switch (avctx->bits_per_sample) {
case 8:
msrle_decode_pal8(s);
break;
case 4:
msrle_decode_pal4(s);
break;
default:
av_log(avctx, AV_LOG_ERROR, "Don't know how to decode depth %u.\n",
avctx->bits_per_sample);
}
if (s->prev_frame.data[0])
avctx->release_buffer(avctx, &s->prev_frame);