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* MJPEG encoder
* Copyright (c) 2000, 2001 Fabrice Bellard
* Copyright (c) 2003 Alex Beregszaszi
* Copyright (c) 2003-2004 Michael Niedermayer
* Support for external huffman table, various fixes (AVID workaround),
* aspecting, new decode_frame mechanism and apple mjpeg-b support
* by Alex Beregszaszi
* This file is part of FFmpeg.
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
* FFmpeg is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* Lesser General Public License for more details.
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
* @file
* MJPEG encoder.
#include <stdint.h>
#include "mjpeg.h"
#include "mpegvideo.h"
#include "put_bits.h"
* Buffer of JPEG frame data.
* Optimal Huffman table generation requires the frame data to be loaded into
* a buffer so that the tables can be computed.
* There are at most mb_width*mb_height*12*64 of these per frame.
typedef struct MJpegHuffmanCode {
// 0=DC lum, 1=DC chrom, 2=AC lum, 3=AC chrom
uint8_t table_id; ///< The Huffman table id associated with the data.
uint8_t code; ///< The exponent.
uint16_t mant; ///< The mantissa.
} MJpegHuffmanCode;
* Holds JPEG frame data and Huffman table data.
typedef struct MJpegContext {
//FIXME use array [3] instead of lumi / chroma, for easier addressing
uint8_t huff_size_dc_luminance[12]; ///< DC luminance Huffman table size.
uint16_t huff_code_dc_luminance[12]; ///< DC luminance Huffman table codes.
uint8_t huff_size_dc_chrominance[12]; ///< DC chrominance Huffman table size.
uint16_t huff_code_dc_chrominance[12]; ///< DC chrominance Huffman table codes.
uint8_t huff_size_ac_luminance[256]; ///< AC luminance Huffman table size.
uint16_t huff_code_ac_luminance[256]; ///< AC luminance Huffman table codes.
uint8_t huff_size_ac_chrominance[256]; ///< AC chrominance Huffman table size.
uint16_t huff_code_ac_chrominance[256]; ///< AC chrominance Huffman table codes.
/** Storage for AC luminance VLC (in MpegEncContext) */
uint8_t uni_ac_vlc_len[64 * 64 * 2];
/** Storage for AC chrominance VLC (in MpegEncContext) */
uint8_t uni_chroma_ac_vlc_len[64 * 64 * 2];
// Default DC tables have exactly 12 values
uint8_t bits_dc_luminance[17]; ///< DC luminance Huffman bits.
uint8_t val_dc_luminance[12]; ///< DC luminance Huffman values.
uint8_t bits_dc_chrominance[17]; ///< DC chrominance Huffman bits.
uint8_t val_dc_chrominance[12]; ///< DC chrominance Huffman values.
// 8-bit JPEG has max 256 values
uint8_t bits_ac_luminance[17]; ///< AC luminance Huffman bits.
uint8_t val_ac_luminance[256]; ///< AC luminance Huffman values.
uint8_t bits_ac_chrominance[17]; ///< AC chrominance Huffman bits.
uint8_t val_ac_chrominance[256]; ///< AC chrominance Huffman values.
size_t huff_ncode; ///< Number of current entries in the buffer.
MJpegHuffmanCode *huff_buffer; ///< Buffer for Huffman code values.
} MJpegContext;
* Enum for the Huffman encoding strategy.
enum HuffmanTableOption {
HUFFMAN_TABLE_DEFAULT = 0, ///< Use the default Huffman tables.
HUFFMAN_TABLE_OPTIMAL = 1, ///< Compute and use optimal Huffman tables.
static inline void put_marker(PutBitContext *p, enum JpegMarker code)
put_bits(p, 8, 0xff);
put_bits(p, 8, code);
int ff_mjpeg_encode_init(MpegEncContext *s);
void ff_mjpeg_encode_close(MpegEncContext *s);
void ff_mjpeg_encode_mb(MpegEncContext *s, int16_t block[12][64]);
int ff_mjpeg_encode_stuffing(MpegEncContext *s);