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FFmpeg/libavcodec/mjpeg.c
Arpi 80e103d04c PATCH by Rik Snel <rsnel@cube.dyndns.org> 
this patch enhances the jpeg header writer. It can be asked to omit
quantisation and huffman tables and it can write different horizontal and
vertical sampling factors. (the last thing is useless for libavcodec
itself (because libavcodec only handles YUV420P at ecoder level), but the
values are initialized so that operation of libavcodec is not impaired)

Originally committed as revision 290 to svn://svn.ffmpeg.org/ffmpeg/trunk
2002-02-09 01:23:41 +00:00

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/*
* MJPEG encoder and decoder
* Copyright (c) 2000, 2001 Gerard Lantau.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
//#define DEBUG
#include "avcodec.h"
#include "dsputil.h"
#include "mpegvideo.h"
typedef struct MJpegContext {
UINT8 huff_size_dc_luminance[12];
UINT16 huff_code_dc_luminance[12];
UINT8 huff_size_dc_chrominance[12];
UINT16 huff_code_dc_chrominance[12];
UINT8 huff_size_ac_luminance[256];
UINT16 huff_code_ac_luminance[256];
UINT8 huff_size_ac_chrominance[256];
UINT16 huff_code_ac_chrominance[256];
} MJpegContext;
#define SOF0 0xc0
#define SOI 0xd8
#define EOI 0xd9
#define DQT 0xdb
#define DHT 0xc4
#define SOS 0xda
#if 0
/* These are the sample quantization tables given in JPEG spec section K.1.
* The spec says that the values given produce "good" quality, and
* when divided by 2, "very good" quality.
*/
static const unsigned char std_luminance_quant_tbl[64] = {
16, 11, 10, 16, 24, 40, 51, 61,
12, 12, 14, 19, 26, 58, 60, 55,
14, 13, 16, 24, 40, 57, 69, 56,
14, 17, 22, 29, 51, 87, 80, 62,
18, 22, 37, 56, 68, 109, 103, 77,
24, 35, 55, 64, 81, 104, 113, 92,
49, 64, 78, 87, 103, 121, 120, 101,
72, 92, 95, 98, 112, 100, 103, 99
};
static const unsigned char std_chrominance_quant_tbl[64] = {
17, 18, 24, 47, 99, 99, 99, 99,
18, 21, 26, 66, 99, 99, 99, 99,
24, 26, 56, 99, 99, 99, 99, 99,
47, 66, 99, 99, 99, 99, 99, 99,
99, 99, 99, 99, 99, 99, 99, 99,
99, 99, 99, 99, 99, 99, 99, 99,
99, 99, 99, 99, 99, 99, 99, 99,
99, 99, 99, 99, 99, 99, 99, 99
};
#endif
/* Set up the standard Huffman tables (cf. JPEG standard section K.3) */
/* IMPORTANT: these are only valid for 8-bit data precision! */
static const UINT8 bits_dc_luminance[17] =
{ /* 0-base */ 0, 0, 1, 5, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0 };
static const UINT8 val_dc_luminance[] =
{ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 };
static const UINT8 bits_dc_chrominance[17] =
{ /* 0-base */ 0, 0, 3, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0 };
static const UINT8 val_dc_chrominance[] =
{ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 };
static const UINT8 bits_ac_luminance[17] =
{ /* 0-base */ 0, 0, 2, 1, 3, 3, 2, 4, 3, 5, 5, 4, 4, 0, 0, 1, 0x7d };
static const UINT8 val_ac_luminance[] =
{ 0x01, 0x02, 0x03, 0x00, 0x04, 0x11, 0x05, 0x12,
0x21, 0x31, 0x41, 0x06, 0x13, 0x51, 0x61, 0x07,
0x22, 0x71, 0x14, 0x32, 0x81, 0x91, 0xa1, 0x08,
0x23, 0x42, 0xb1, 0xc1, 0x15, 0x52, 0xd1, 0xf0,
0x24, 0x33, 0x62, 0x72, 0x82, 0x09, 0x0a, 0x16,
0x17, 0x18, 0x19, 0x1a, 0x25, 0x26, 0x27, 0x28,
0x29, 0x2a, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39,
0x3a, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48, 0x49,
0x4a, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58, 0x59,
0x5a, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68, 0x69,
0x6a, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78, 0x79,
0x7a, 0x83, 0x84, 0x85, 0x86, 0x87, 0x88, 0x89,
0x8a, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97, 0x98,
0x99, 0x9a, 0xa2, 0xa3, 0xa4, 0xa5, 0xa6, 0xa7,
0xa8, 0xa9, 0xaa, 0xb2, 0xb3, 0xb4, 0xb5, 0xb6,
0xb7, 0xb8, 0xb9, 0xba, 0xc2, 0xc3, 0xc4, 0xc5,
0xc6, 0xc7, 0xc8, 0xc9, 0xca, 0xd2, 0xd3, 0xd4,
0xd5, 0xd6, 0xd7, 0xd8, 0xd9, 0xda, 0xe1, 0xe2,
0xe3, 0xe4, 0xe5, 0xe6, 0xe7, 0xe8, 0xe9, 0xea,
0xf1, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7, 0xf8,
0xf9, 0xfa
};
static const UINT8 bits_ac_chrominance[17] =
{ /* 0-base */ 0, 0, 2, 1, 2, 4, 4, 3, 4, 7, 5, 4, 4, 0, 1, 2, 0x77 };
static const UINT8 val_ac_chrominance[] =
{ 0x00, 0x01, 0x02, 0x03, 0x11, 0x04, 0x05, 0x21,
0x31, 0x06, 0x12, 0x41, 0x51, 0x07, 0x61, 0x71,
0x13, 0x22, 0x32, 0x81, 0x08, 0x14, 0x42, 0x91,
0xa1, 0xb1, 0xc1, 0x09, 0x23, 0x33, 0x52, 0xf0,
0x15, 0x62, 0x72, 0xd1, 0x0a, 0x16, 0x24, 0x34,
0xe1, 0x25, 0xf1, 0x17, 0x18, 0x19, 0x1a, 0x26,
0x27, 0x28, 0x29, 0x2a, 0x35, 0x36, 0x37, 0x38,
0x39, 0x3a, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48,
0x49, 0x4a, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58,
0x59, 0x5a, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68,
0x69, 0x6a, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78,
0x79, 0x7a, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87,
0x88, 0x89, 0x8a, 0x92, 0x93, 0x94, 0x95, 0x96,
0x97, 0x98, 0x99, 0x9a, 0xa2, 0xa3, 0xa4, 0xa5,
0xa6, 0xa7, 0xa8, 0xa9, 0xaa, 0xb2, 0xb3, 0xb4,
0xb5, 0xb6, 0xb7, 0xb8, 0xb9, 0xba, 0xc2, 0xc3,
0xc4, 0xc5, 0xc6, 0xc7, 0xc8, 0xc9, 0xca, 0xd2,
0xd3, 0xd4, 0xd5, 0xd6, 0xd7, 0xd8, 0xd9, 0xda,
0xe2, 0xe3, 0xe4, 0xe5, 0xe6, 0xe7, 0xe8, 0xe9,
0xea, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7, 0xf8,
0xf9, 0xfa
};
/* isn't this function nicer than the one in the libjpeg ? */
static void build_huffman_codes(UINT8 *huff_size, UINT16 *huff_code,
const UINT8 *bits_table, const UINT8 *val_table)
{
int i, j, k,nb, code, sym;
code = 0;
k = 0;
for(i=1;i<=16;i++) {
nb = bits_table[i];
for(j=0;j<nb;j++) {
sym = val_table[k++];
huff_size[sym] = i;
huff_code[sym] = code;
code++;
}
code <<= 1;
}
}
int mjpeg_init(MpegEncContext *s)
{
MJpegContext *m;
m = malloc(sizeof(MJpegContext));
if (!m)
return -1;
/* build all the huffman tables */
build_huffman_codes(m->huff_size_dc_luminance,
m->huff_code_dc_luminance,
bits_dc_luminance,
val_dc_luminance);
build_huffman_codes(m->huff_size_dc_chrominance,
m->huff_code_dc_chrominance,
bits_dc_chrominance,
val_dc_chrominance);
build_huffman_codes(m->huff_size_ac_luminance,
m->huff_code_ac_luminance,
bits_ac_luminance,
val_ac_luminance);
build_huffman_codes(m->huff_size_ac_chrominance,
m->huff_code_ac_chrominance,
bits_ac_chrominance,
val_ac_chrominance);
s->mjpeg_ctx = m;
return 0;
}
void mjpeg_close(MpegEncContext *s)
{
free(s->mjpeg_ctx);
}
static inline void put_marker(PutBitContext *p, int code)
{
put_bits(p, 8, 0xff);
put_bits(p, 8, code);
}
/* table_class: 0 = DC coef, 1 = AC coefs */
static int put_huffman_table(MpegEncContext *s, int table_class, int table_id,
const UINT8 *bits_table, const UINT8 *value_table)
{
PutBitContext *p = &s->pb;
int n, i;
put_bits(p, 4, table_class);
put_bits(p, 4, table_id);
n = 0;
for(i=1;i<=16;i++) {
n += bits_table[i];
put_bits(p, 8, bits_table[i]);
}
for(i=0;i<n;i++)
put_bits(p, 8, value_table[i]);
return n + 17;
}
static void jpeg_table_header(MpegEncContext *s)
{
PutBitContext *p = &s->pb;
int i, j, size;
UINT8 *ptr;
/* quant matrixes */
put_marker(p, DQT);
put_bits(p, 16, 2 + 1 * (1 + 64));
put_bits(p, 4, 0); /* 8 bit precision */
put_bits(p, 4, 0); /* table 0 */
for(i=0;i<64;i++) {
j = zigzag_direct[i];
put_bits(p, 8, s->intra_matrix[j]);
}
#if 0
put_bits(p, 4, 0); /* 8 bit precision */
put_bits(p, 4, 1); /* table 1 */
for(i=0;i<64;i++) {
j = zigzag_direct[i];
put_bits(p, 8, s->chroma_intra_matrix[j]);
}
#endif
/* huffman table */
put_marker(p, DHT);
flush_put_bits(p);
ptr = p->buf_ptr;
put_bits(p, 16, 0); /* patched later */
size = 2;
size += put_huffman_table(s, 0, 0, bits_dc_luminance, val_dc_luminance);
size += put_huffman_table(s, 0, 1, bits_dc_chrominance, val_dc_chrominance);
size += put_huffman_table(s, 1, 0, bits_ac_luminance, val_ac_luminance);
size += put_huffman_table(s, 1, 1, bits_ac_chrominance, val_ac_chrominance);
ptr[0] = size >> 8;
ptr[1] = size;
}
void mjpeg_picture_header(MpegEncContext *s)
{
put_marker(&s->pb, SOI);
if (s->mjpeg_write_tables) jpeg_table_header(s);
put_marker(&s->pb, SOF0);
put_bits(&s->pb, 16, 17);
put_bits(&s->pb, 8, 8); /* 8 bits/component */
put_bits(&s->pb, 16, s->height);
put_bits(&s->pb, 16, s->width);
put_bits(&s->pb, 8, 3); /* 3 components */
/* Y component */
put_bits(&s->pb, 8, 1); /* component number */
put_bits(&s->pb, 4, s->mjpeg_hsample[0]); /* H factor */
put_bits(&s->pb, 4, s->mjpeg_vsample[0]); /* V factor */
put_bits(&s->pb, 8, 0); /* select matrix */
/* Cb component */
put_bits(&s->pb, 8, 2); /* component number */
put_bits(&s->pb, 4, s->mjpeg_hsample[1]); /* H factor */
put_bits(&s->pb, 4, s->mjpeg_vsample[1]); /* V factor */
put_bits(&s->pb, 8, 0); /* select matrix */
/* Cr component */
put_bits(&s->pb, 8, 3); /* component number */
put_bits(&s->pb, 4, s->mjpeg_hsample[2]); /* H factor */
put_bits(&s->pb, 4, s->mjpeg_vsample[2]); /* V factor */
put_bits(&s->pb, 8, 0); /* select matrix */
/* scan header */
put_marker(&s->pb, SOS);
put_bits(&s->pb, 16, 12); /* length */
put_bits(&s->pb, 8, 3); /* 3 components */
/* Y component */
put_bits(&s->pb, 8, 1); /* index */
put_bits(&s->pb, 4, 0); /* DC huffman table index */
put_bits(&s->pb, 4, 0); /* AC huffman table index */
/* Cb component */
put_bits(&s->pb, 8, 2); /* index */
put_bits(&s->pb, 4, 1); /* DC huffman table index */
put_bits(&s->pb, 4, 1); /* AC huffman table index */
/* Cr component */
put_bits(&s->pb, 8, 3); /* index */
put_bits(&s->pb, 4, 1); /* DC huffman table index */
put_bits(&s->pb, 4, 1); /* AC huffman table index */
put_bits(&s->pb, 8, 0); /* Ss (not used) */
put_bits(&s->pb, 8, 63); /* Se (not used) */
put_bits(&s->pb, 8, 0); /* (not used) */
}
void mjpeg_picture_trailer(MpegEncContext *s)
{
jflush_put_bits(&s->pb);
put_marker(&s->pb, EOI);
}
static inline void encode_dc(MpegEncContext *s, int val,
UINT8 *huff_size, UINT16 *huff_code)
{
int mant, nbits;
if (val == 0) {
jput_bits(&s->pb, huff_size[0], huff_code[0]);
} else {
mant = val;
if (val < 0) {
val = -val;
mant--;
}
/* compute the log (XXX: optimize) */
nbits = 0;
while (val != 0) {
val = val >> 1;
nbits++;
}
jput_bits(&s->pb, huff_size[nbits], huff_code[nbits]);
jput_bits(&s->pb, nbits, mant & ((1 << nbits) - 1));
}
}
static void encode_block(MpegEncContext *s, DCTELEM *block, int n)
{
int mant, nbits, code, i, j;
int component, dc, run, last_index, val;
MJpegContext *m = s->mjpeg_ctx;
UINT8 *huff_size_ac;
UINT16 *huff_code_ac;
/* DC coef */
component = (n <= 3 ? 0 : n - 4 + 1);
dc = block[0]; /* overflow is impossible */
val = dc - s->last_dc[component];
if (n < 4) {
encode_dc(s, val, m->huff_size_dc_luminance, m->huff_code_dc_luminance);
huff_size_ac = m->huff_size_ac_luminance;
huff_code_ac = m->huff_code_ac_luminance;
} else {
encode_dc(s, val, m->huff_size_dc_chrominance, m->huff_code_dc_chrominance);
huff_size_ac = m->huff_size_ac_chrominance;
huff_code_ac = m->huff_code_ac_chrominance;
}
s->last_dc[component] = dc;
/* AC coefs */
run = 0;
last_index = s->block_last_index[n];
for(i=1;i<=last_index;i++) {
j = zigzag_direct[i];
val = block[j];
if (val == 0) {
run++;
} else {
while (run >= 16) {
jput_bits(&s->pb, huff_size_ac[0xf0], huff_code_ac[0xf0]);
run -= 16;
}
mant = val;
if (val < 0) {
val = -val;
mant--;
}
/* compute the log (XXX: optimize) */
nbits = 0;
while (val != 0) {
val = val >> 1;
nbits++;
}
code = (run << 4) | nbits;
jput_bits(&s->pb, huff_size_ac[code], huff_code_ac[code]);
jput_bits(&s->pb, nbits, mant & ((1 << nbits) - 1));
run = 0;
}
}
/* output EOB only if not already 64 values */
if (last_index < 63 || run != 0)
jput_bits(&s->pb, huff_size_ac[0], huff_code_ac[0]);
}
void mjpeg_encode_mb(MpegEncContext *s,
DCTELEM block[6][64])
{
int i;
for(i=0;i<6;i++) {
encode_block(s, block[i], i);
}
}
/******************************************/
/* decoding */
/* compressed picture size */
#define PICTURE_BUFFER_SIZE 100000
#define MAX_COMPONENTS 4
typedef struct MJpegDecodeContext {
GetBitContext gb;
UINT32 header_state;
int start_code; /* current start code */
UINT8 *buf_ptr;
int buffer_size;
int mpeg_enc_ctx_allocated; /* true if decoding context allocated */
INT16 quant_matrixes[4][64];
VLC vlcs[2][4];
int org_width, org_height; /* size given at codec init */
int first_picture; /* true if decoding first picture */
int interlaced; /* true if interlaced */
int bottom_field; /* true if bottom field */
int width, height;
int nb_components;
int component_id[MAX_COMPONENTS];
int h_count[MAX_COMPONENTS]; /* horizontal and vertical count for each component */
int v_count[MAX_COMPONENTS];
int h_max, v_max; /* maximum h and v counts */
int quant_index[4]; /* quant table index for each component */
int last_dc[MAX_COMPONENTS]; /* last DEQUANTIZED dc (XXX: am I right to do that ?) */
UINT8 *current_picture[MAX_COMPONENTS]; /* picture structure */
int linesize[MAX_COMPONENTS];
DCTELEM block[64] __align8;
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;
s->header_state = 0;
s->mpeg_enc_ctx_allocated = 0;
s->buffer_size = PICTURE_BUFFER_SIZE - 1; /* minus 1 to take into
account FF 00 case */
s->start_code = -1;
s->buf_ptr = s->buffer;
s->first_picture = 1;
s->org_width = avctx->width;
s->org_height = avctx->height;
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;
}
/* quantize tables */
static int mjpeg_decode_dqt(MJpegDecodeContext *s,
UINT8 *buf, int buf_size)
{
int len, index, i, j;
init_get_bits(&s->gb, buf, buf_size);
len = get_bits(&s->gb, 16);
len -= 2;
while (len >= 65) {
/* only 8 bit precision handled */
if (get_bits(&s->gb, 4) != 0)
return -1;
index = get_bits(&s->gb, 4);
if (index >= 4)
return -1;
dprintf("index=%d\n", index);
/* read quant table */
for(i=0;i<64;i++) {
j = zigzag_direct[i];
s->quant_matrixes[index][j] = get_bits(&s->gb, 8);
}
len -= 65;
}
return 0;
}
/* decode huffman tables and build VLC decoders */
static int mjpeg_decode_dht(MJpegDecodeContext *s,
UINT8 *buf, int buf_size)
{
int len, index, i, class, n, v, code_max;
UINT8 bits_table[17];
UINT8 val_table[256];
init_get_bits(&s->gb, buf, buf_size);
len = get_bits(&s->gb, 16);
len -= 2;
while (len > 0) {
if (len < 17)
return -1;
class = get_bits(&s->gb, 4);
if (class >= 2)
return -1;
index = get_bits(&s->gb, 4);
if (index >= 4)
return -1;
n = 0;
for(i=1;i<=16;i++) {
bits_table[i] = get_bits(&s->gb, 8);
n += bits_table[i];
}
len -= 17;
if (len < n || n > 256)
return -1;
code_max = 0;
for(i=0;i<n;i++) {
v = get_bits(&s->gb, 8);
if (v > code_max)
code_max = v;
val_table[i] = v;
}
len -= n;
/* 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);
build_vlc(&s->vlcs[class][index], bits_table, val_table, code_max + 1);
}
return 0;
}
static int mjpeg_decode_sof0(MJpegDecodeContext *s,
UINT8 *buf, int buf_size)
{
int len, nb_components, i, width, height;
init_get_bits(&s->gb, buf, buf_size);
/* XXX: verify len field validity */
len = get_bits(&s->gb, 16);
/* only 8 bits/component accepted */
if (get_bits(&s->gb, 8) != 8)
return -1;
height = get_bits(&s->gb, 16);
width = get_bits(&s->gb, 16);
nb_components = get_bits(&s->gb, 8);
if (nb_components <= 0 ||
nb_components > MAX_COMPONENTS)
return -1;
s->nb_components = nb_components;
s->h_max = 1;
s->v_max = 1;
for(i=0;i<nb_components;i++) {
/* component id */
s->component_id[i] = get_bits(&s->gb, 8) - 1;
s->h_count[i] = get_bits(&s->gb, 4);
s->v_count[i] = get_bits(&s->gb, 4);
/* compute hmax and vmax (only used in interleaved case) */
if (s->h_count[i] > s->h_max)
s->h_max = s->h_count[i];
if (s->v_count[i] > s->v_max)
s->v_max = s->v_count[i];
s->quant_index[i] = get_bits(&s->gb, 8);
if (s->quant_index[i] >= 4)
return -1;
dprintf("component %d %d:%d\n", i, s->h_count[i], s->v_count[i]);
}
/* if different size, realloc/alloc picture */
/* XXX: also check h_count and v_count */
if (width != s->width || height != s->height) {
for(i=0;i<MAX_COMPONENTS;i++) {
free(s->current_picture[i]);
s->current_picture[i] = NULL;
}
s->width = width;
s->height = height;
/* test interlaced mode */
if (s->first_picture &&
s->org_height != 0 &&
s->height < ((s->org_height * 3) / 4)) {
s->interlaced = 1;
s->bottom_field = 0;
}
for(i=0;i<nb_components;i++) {
int w, h;
w = (s->width + 8 * s->h_max - 1) / (8 * s->h_max);
h = (s->height + 8 * s->v_max - 1) / (8 * s->v_max);
w = w * 8 * s->h_count[i];
h = h * 8 * s->v_count[i];
if (s->interlaced)
w *= 2;
s->linesize[i] = w;
/* memory test is done in mjpeg_decode_sos() */
s->current_picture[i] = av_mallocz(w * h);
}
s->first_picture = 0;
}
return 0;
}
static inline int decode_dc(MJpegDecodeContext *s, int dc_index)
{
VLC *dc_vlc;
int code, diff;
dc_vlc = &s->vlcs[0][dc_index];
code = get_vlc(&s->gb, dc_vlc);
if (code < 0)
return 0xffff;
if (code == 0) {
diff = 0;
} else {
diff = get_bits(&s->gb, code);
if ((diff & (1 << (code - 1))) == 0)
diff = (-1 << code) | (diff + 1);
}
return diff;
}
/* decode block and dequantize */
static int decode_block(MJpegDecodeContext *s, DCTELEM *block,
int component, int dc_index, int ac_index, int quant_index)
{
int nbits, code, i, j, level;
int run, val;
VLC *ac_vlc;
INT16 *quant_matrix;
quant_matrix = s->quant_matrixes[quant_index];
/* DC coef */
val = decode_dc(s, dc_index);
if (val == 0xffff) {
dprintf("error dc\n");
return -1;
}
val = val * quant_matrix[0] + s->last_dc[component];
s->last_dc[component] = val;
block[0] = val;
/* AC coefs */
ac_vlc = &s->vlcs[1][ac_index];
i = 1;
for(;;) {
code = get_vlc(&s->gb, ac_vlc);
if (code < 0) {
dprintf("error ac\n");
return -1;
}
/* EOB */
if (code == 0)
break;
if (code == 0xf0) {
i += 16;
} else {
run = code >> 4;
nbits = code & 0xf;
level = get_bits(&s->gb, nbits);
if ((level & (1 << (nbits - 1))) == 0)
level = (-1 << nbits) | (level + 1);
i += run;
if (i >= 64) {
dprintf("error count: %d\n", i);
return -1;
}
j = zigzag_direct[i];
block[j] = level * quant_matrix[j];
i++;
if (i >= 64)
break;
}
}
return 0;
}
static int mjpeg_decode_sos(MJpegDecodeContext *s,
UINT8 *buf, int buf_size)
{
int len, nb_components, i, j, n, h, v, ret;
int mb_width, mb_height, mb_x, mb_y, vmax, hmax, index, id;
int comp_index[4];
int dc_index[4];
int ac_index[4];
int nb_blocks[4];
int h_count[4];
int v_count[4];
init_get_bits(&s->gb, buf, buf_size);
/* XXX: verify len field validity */
len = get_bits(&s->gb, 16);
nb_components = get_bits(&s->gb, 8);
/* XXX: only interleaved scan accepted */
if (nb_components != 3)
return -1;
vmax = 0;
hmax = 0;
for(i=0;i<nb_components;i++) {
id = get_bits(&s->gb, 8) - 1;
/* find component index */
for(index=0;index<s->nb_components;index++)
if (id == s->component_id[index])
break;
if (index == s->nb_components)
return -1;
comp_index[i] = index;
nb_blocks[i] = s->h_count[index] * s->v_count[index];
h_count[i] = s->h_count[index];
v_count[i] = s->v_count[index];
dc_index[i] = get_bits(&s->gb, 4);
if (dc_index[i] >= 4)
return -1;
ac_index[i] = get_bits(&s->gb, 4);
if (ac_index[i] >= 4)
return -1;
}
get_bits(&s->gb, 8); /* Ss */
get_bits(&s->gb, 8); /* Se */
get_bits(&s->gb, 8); /* not used */
for(i=0;i<nb_components;i++)
s->last_dc[i] = 1024;
if (nb_components > 1) {
/* interleaved stream */
mb_width = (s->width + s->h_max * 8 - 1) / (s->h_max * 8);
mb_height = (s->height + s->v_max * 8 - 1) / (s->v_max * 8);
} else {
h = s->h_max / s->h_count[comp_index[0]];
v = s->v_max / s->v_count[comp_index[0]];
mb_width = (s->width + h * 8 - 1) / (h * 8);
mb_height = (s->height + v * 8 - 1) / (v * 8);
nb_blocks[0] = 1;
h_count[0] = 1;
v_count[0] = 1;
}
for(mb_y = 0; mb_y < mb_height; mb_y++) {
for(mb_x = 0; mb_x < mb_width; mb_x++) {
for(i=0;i<nb_components;i++) {
UINT8 *ptr;
int x, y, c;
n = nb_blocks[i];
c = comp_index[i];
h = h_count[i];
v = v_count[i];
x = 0;
y = 0;
for(j=0;j<n;j++) {
memset(s->block, 0, sizeof(s->block));
if (decode_block(s, s->block, i,
dc_index[i], ac_index[i],
s->quant_index[c]) < 0) {
dprintf("error %d %d\n", mb_y, mb_x);
ret = -1;
goto the_end;
}
ff_idct (s->block);
ptr = s->current_picture[c] +
(s->linesize[c] * (v * mb_y + y) * 8) +
(h * mb_x + x) * 8;
if (s->interlaced && s->bottom_field)
ptr += s->linesize[c] >> 1;
put_pixels_clamped(s->block, ptr, s->linesize[c]);
if (++x == h) {
x = 0;
y++;
}
}
}
}
}
ret = 0;
the_end:
emms_c();
return ret;
}
/* return the 8 bit start code value and update the search
state. Return -1 if no start code found */
static int find_marker(UINT8 **pbuf_ptr, UINT8 *buf_end,
UINT32 *header_state)
{
UINT8 *buf_ptr;
unsigned int state, v;
int val;
state = *header_state;
buf_ptr = *pbuf_ptr;
if (state) {
/* get marker */
found:
if (buf_ptr < buf_end) {
val = *buf_ptr++;
state = 0;
} else {
val = -1;
}
} else {
while (buf_ptr < buf_end) {
v = *buf_ptr++;
if (v == 0xff) {
state = 1;
goto found;
}
}
val = -1;
}
*pbuf_ptr = buf_ptr;
*header_state = state;
return val;
}
static int mjpeg_decode_frame(AVCodecContext *avctx,
void *data, int *data_size,
UINT8 *buf, int buf_size)
{
MJpegDecodeContext *s = avctx->priv_data;
UINT8 *buf_end, *buf_ptr, *buf_start;
int len, code, start_code, input_size, i;
AVPicture *picture = data;
*data_size = 0;
/* no supplementary picture */
if (buf_size == 0)
return 0;
buf_ptr = buf;
buf_end = buf + buf_size;
while (buf_ptr < buf_end) {
buf_start = buf_ptr;
/* find start next marker */
code = find_marker(&buf_ptr, buf_end, &s->header_state);
/* copy to buffer */
len = buf_ptr - buf_start;
if (len + (s->buf_ptr - s->buffer) > s->buffer_size) {
/* data too big : flush */
s->buf_ptr = s->buffer;
if (code > 0)
s->start_code = code;
} else {
memcpy(s->buf_ptr, buf_start, len);
s->buf_ptr += len;
/* if we got FF 00, we copy FF to the stream to unescape FF 00 */
if (code == 0) {
s->buf_ptr--;
} else if (code > 0) {
/* prepare data for next start code */
input_size = s->buf_ptr - s->buffer;
start_code = s->start_code;
s->buf_ptr = s->buffer;
s->start_code = code;
dprintf("marker=%x\n", start_code);
switch(start_code) {
case SOI:
/* nothing to do on SOI */
break;
case DQT:
mjpeg_decode_dqt(s, s->buffer, input_size);
break;
case DHT:
mjpeg_decode_dht(s, s->buffer, input_size);
break;
case SOF0:
mjpeg_decode_sof0(s, s->buffer, input_size);
break;
case SOS:
mjpeg_decode_sos(s, s->buffer, input_size);
if (s->start_code == EOI) {
int l;
if (s->interlaced) {
s->bottom_field ^= 1;
/* if not bottom field, do not output image yet */
if (s->bottom_field)
goto the_end;
}
for(i=0;i<3;i++) {
picture->data[i] = s->current_picture[i];
l = s->linesize[i];
if (s->interlaced)
l >>= 1;
picture->linesize[i] = l;
}
*data_size = sizeof(AVPicture);
avctx->height = s->height;
if (s->interlaced)
avctx->height *= 2;
avctx->width = s->width;
/* XXX: not complete test ! */
switch((s->h_count[0] << 4) | s->v_count[0]) {
case 0x11:
avctx->pix_fmt = PIX_FMT_YUV444P;
break;
case 0x21:
avctx->pix_fmt = PIX_FMT_YUV422P;
break;
default:
case 0x22:
avctx->pix_fmt = PIX_FMT_YUV420P;
break;
}
/* dummy quality */
/* XXX: infer it with matrix */
avctx->quality = 3;
goto the_end;
}
break;
}
}
}
}
the_end:
return buf_ptr - buf;
}
static int mjpeg_decode_end(AVCodecContext *avctx)
{
MJpegDecodeContext *s = avctx->priv_data;
int i, j;
for(i=0;i<MAX_COMPONENTS;i++)
free(s->current_picture[i]);
for(i=0;i<2;i++) {
for(j=0;j<4;j++)
free_vlc(&s->vlcs[i][j]);
}
return 0;
}
AVCodec mjpeg_decoder = {
"mjpeg",
CODEC_TYPE_VIDEO,
CODEC_ID_MJPEG,
sizeof(MJpegDecodeContext),
mjpeg_decode_init,
NULL,
mjpeg_decode_end,
mjpeg_decode_frame,
};
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