generic-library/ffmpeg
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use default huffman tables if none given

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Originally committed as revision 40 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Fabrice Bellard 2001-08-06 02:46:46 +00:00
parent b182e68ac5
commit bbc0d0c1fe
1 changed files with 18 additions and 9 deletions
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27
libavcodec/mjpeg.c
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@ -455,6 +455,18 @@ typedef struct MJpegDecodeContext {
UINT8 buffer[PICTURE_BUFFER_SIZE];
} MJpegDecodeContext;
static void build_vlc(VLC *vlc, const UINT8 *bits_table, const UINT8 *val_table,
int nb_codes)
{
UINT8 huff_size[256];
UINT16 huff_code[256];
memset(huff_size, 0, sizeof(huff_size));
build_huffman_codes(huff_size, huff_code, bits_table, val_table);
init_vlc(vlc, 9, nb_codes, huff_size, 1, 1, huff_code, 2, 2);
}
static int mjpeg_decode_init(AVCodecContext *avctx)
{
MJpegDecodeContext *s = avctx->priv_data;
@ -465,6 +477,11 @@ static int mjpeg_decode_init(AVCodecContext *avctx)
account FF 00 case */
s->start_code = -1;
s->buf_ptr = s->buffer;
build_vlc(&s->vlcs[0][0], bits_dc_luminance, val_dc_luminance, 12);
build_vlc(&s->vlcs[0][1], bits_dc_chrominance, val_dc_chrominance, 12);
build_vlc(&s->vlcs[1][0], bits_ac_luminance, val_ac_luminance, 251);
build_vlc(&s->vlcs[1][1], bits_ac_chrominance, val_ac_chrominance, 251);
return 0;
}
@ -501,8 +518,6 @@ static int mjpeg_decode_dht(MJpegDecodeContext *s,
int len, index, i, class, n, v, code_max;
UINT8 bits_table[17];
UINT8 val_table[256];
UINT8 huff_size[256];
UINT16 huff_code[256];
init_get_bits(&s->gb, buf, buf_size);
@ -536,17 +551,11 @@ static int mjpeg_decode_dht(MJpegDecodeContext *s,
}
len -= n;
/* now build size/code table */
memset(huff_size, 0, sizeof(huff_size));
build_huffman_codes(huff_size, huff_code, bits_table, val_table);
/* build VLC and flush previous vlc if present */
free_vlc(&s->vlcs[class][index]);
dprintf("class=%d index=%d nb_codes=%d\n",
class, index, code_max + 1);
init_vlc(&s->vlcs[class][index], 9, code_max + 1,
huff_size, 1, 1,
huff_code, 2, 2);
build_vlc(&s->vlcs[class][index], bits_table, val_table, code_max + 1);
}
return 0;
}