mirror of https://github.com/mpv-player/mpv
126 lines
2.7 KiB
C
126 lines
2.7 KiB
C
/*
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Quicktime Animation (RLE) Decoder for MPlayer
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(C) 2001 Mike Melanson
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*/
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#include "config.h"
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#include "bswap.h"
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#define BE_16(x) (be2me_16(*(unsigned short *)(x)))
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#define BE_32(x) (be2me_32(*(unsigned int *)(x)))
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// 256 RGB entries; 25% of these bytes will be unused, but it's faster
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// to index 4-byte entries
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static unsigned char palette[256 * 4];
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void qt_decode_rle24(
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unsigned char *encoded,
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int encoded_size,
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unsigned char *decoded,
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int width,
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int height,
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int bytes_per_pixel)
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{
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int stream_ptr;
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int header;
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int start_line;
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int lines_to_change;
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signed char rle_code;
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int row_ptr, pixel_ptr;
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int row_inc = bytes_per_pixel * width;
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unsigned char r, g, b;
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// check if this frame is even supposed to change
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if (encoded_size < 8)
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return;
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// start after the chunk size
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stream_ptr = 4;
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// fetch the header
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header = BE_16(&encoded[stream_ptr]);
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stream_ptr += 2;
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// if a header is present, fetch additional decoding parameters
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if (header & 0x0008)
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{
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start_line = BE_16(&encoded[stream_ptr]);
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stream_ptr += 4;
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lines_to_change = BE_16(&encoded[stream_ptr]);
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stream_ptr += 4;
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}
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else
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{
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start_line = 0;
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lines_to_change = height;
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}
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row_ptr = row_inc * start_line;
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while (lines_to_change--)
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{
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pixel_ptr = row_ptr + ((encoded[stream_ptr++] - 1) * bytes_per_pixel);
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while ((rle_code = (signed char)encoded[stream_ptr++]) != -1)
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{
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if (rle_code == 0)
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// there's another skip code in the stream
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pixel_ptr += ((encoded[stream_ptr++] - 1) * bytes_per_pixel);
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else if (rle_code < 0)
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{
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// decode the run length code
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rle_code = -rle_code;
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r = encoded[stream_ptr++];
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g = encoded[stream_ptr++];
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b = encoded[stream_ptr++];
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while (rle_code--)
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{
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decoded[pixel_ptr++] = b;
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decoded[pixel_ptr++] = g;
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decoded[pixel_ptr++] = r;
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if (bytes_per_pixel == 4)
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pixel_ptr++;
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}
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}
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else
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{
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// copy pixels directly to output
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while (rle_code--)
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{
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decoded[pixel_ptr++] = encoded[stream_ptr + 2];
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decoded[pixel_ptr++] = encoded[stream_ptr + 1];
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decoded[pixel_ptr++] = encoded[stream_ptr + 0];
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stream_ptr += 3;
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if (bytes_per_pixel == 4)
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pixel_ptr++;
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}
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}
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}
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row_ptr += row_inc;
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}
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}
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void qt_decode_rle(
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unsigned char *encoded,
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int encoded_size,
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unsigned char *decoded,
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int width,
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int height,
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int encoded_bpp,
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int bytes_per_pixel)
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{
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switch (encoded_bpp)
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{
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case 24:
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qt_decode_rle24(
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encoded,
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encoded_size,
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decoded,
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width,
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height,
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bytes_per_pixel);
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break;
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}
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}
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