FFmpeg/libavcodec/mjpegenc_common.c

/*
 * lossless JPEG shared bits
 *
 * This file is part of Libav.
 *
 * Libav 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.
 *
 * Libav 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with Libav; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

#include <stdint.h>
#include <string.h>

#include "libavutil/common.h"
#include "libavutil/pixdesc.h"
#include "libavutil/pixfmt.h"

#include "avcodec.h"
#include "idctdsp.h"
#include "put_bits.h"
#include "mjpegenc_common.h"
#include "mjpeg.h"

/* table_class: 0 = DC coef, 1 = AC coefs */
static int put_huffman_table(PutBitContext *p, int table_class, int table_id,
                             const uint8_t *bits_table, const uint8_t *value_table)
{
    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(PutBitContext *p, ScanTable *intra_scantable,
                              uint16_t intra_matrix[64])
{
    int i, j, size;
    uint8_t *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 = intra_scantable->permutated[i];
        put_bits(p, 8, intra_matrix[j]);
    }

    /* huffman table */
    put_marker(p, DHT);
    flush_put_bits(p);
    ptr = put_bits_ptr(p);
    put_bits(p, 16, 0); /* patched later */
    size = 2;
    size += put_huffman_table(p, 0, 0, avpriv_mjpeg_bits_dc_luminance,
                              avpriv_mjpeg_val_dc);
    size += put_huffman_table(p, 0, 1, avpriv_mjpeg_bits_dc_chrominance,
                              avpriv_mjpeg_val_dc);

    size += put_huffman_table(p, 1, 0, avpriv_mjpeg_bits_ac_luminance,
                              avpriv_mjpeg_val_ac_luminance);
    size += put_huffman_table(p, 1, 1, avpriv_mjpeg_bits_ac_chrominance,
                              avpriv_mjpeg_val_ac_chrominance);
    AV_WB16(ptr, size);
}

static void jpeg_put_comments(AVCodecContext *avctx, PutBitContext *p)
{
    int size;
    uint8_t *ptr;

    if (avctx->sample_aspect_ratio.num > 0 && avctx->sample_aspect_ratio.den > 0) {
        /* JFIF header */
        put_marker(p, APP0);
        put_bits(p, 16, 16);
        avpriv_put_string(p, "JFIF", 1); /* this puts the trailing zero-byte too */
        put_bits(p, 16, 0x0201);         /* v 1.02 */
        put_bits(p,  8, 0);              /* units type: 0 - aspect ratio */
        put_bits(p, 16, avctx->sample_aspect_ratio.num);
        put_bits(p, 16, avctx->sample_aspect_ratio.den);
        put_bits(p, 8, 0); /* thumbnail width */
        put_bits(p, 8, 0); /* thumbnail height */
    }

    /* comment */
    if (!(avctx->flags & CODEC_FLAG_BITEXACT)) {
        put_marker(p, COM);
        flush_put_bits(p);
        ptr = put_bits_ptr(p);
        put_bits(p, 16, 0); /* patched later */
        avpriv_put_string(p, LIBAVCODEC_IDENT, 1);
        size = strlen(LIBAVCODEC_IDENT)+3;
        AV_WB16(ptr, size);
    }

    if (avctx->pix_fmt == AV_PIX_FMT_YUV420P ||
        avctx->pix_fmt == AV_PIX_FMT_YUV422P ||
        avctx->pix_fmt == AV_PIX_FMT_YUV444P) {
        put_marker(p, COM);
        flush_put_bits(p);
        ptr = put_bits_ptr(p);
        put_bits(p, 16, 0); /* patched later */
        avpriv_put_string(p, "CS=ITU601", 1);
        size = strlen("CS=ITU601")+3;
        AV_WB16(ptr, size);
    }
}

void ff_mjpeg_encode_picture_header(AVCodecContext *avctx, PutBitContext *pb,
                                    ScanTable *intra_scantable,
                                    uint16_t intra_matrix[64])
{
    int chroma_h_shift, chroma_v_shift;
    const int lossless = avctx->codec_id != AV_CODEC_ID_MJPEG;
    int hsample[3], vsample[3];

    av_pix_fmt_get_chroma_sub_sample(avctx->pix_fmt, &chroma_h_shift,
                                     &chroma_v_shift);

    if (avctx->codec->id == AV_CODEC_ID_LJPEG &&
        avctx->pix_fmt   == AV_PIX_FMT_BGR24) {
        vsample[0] = hsample[0] =
        vsample[1] = hsample[1] =
        vsample[2] = hsample[2] = 1;
    } else {
        vsample[0] = 2;
        vsample[1] = 2 >> chroma_v_shift;
        vsample[2] = 2 >> chroma_v_shift;
        hsample[0] = 2;
        hsample[1] = 2 >> chroma_h_shift;
        hsample[2] = 2 >> chroma_h_shift;
    }

    put_marker(pb, SOI);

    jpeg_put_comments(avctx, pb);

    jpeg_table_header(pb, intra_scantable, intra_matrix);

    switch (avctx->codec_id) {
    case AV_CODEC_ID_MJPEG:  put_marker(pb, SOF0 ); break;
    case AV_CODEC_ID_LJPEG:  put_marker(pb, SOF3 ); break;
    default: assert(0);
    }

    put_bits(pb, 16, 17);
    if (lossless && avctx->pix_fmt == AV_PIX_FMT_BGR24)
        put_bits(pb, 8, 9); /* 9 bits/component RCT */
    else
        put_bits(pb, 8, 8); /* 8 bits/component */
    put_bits(pb, 16, avctx->height);
    put_bits(pb, 16, avctx->width);
    put_bits(pb, 8, 3); /* 3 components */

    /* Y component */
    put_bits(pb, 8, 1); /* component number */
    put_bits(pb, 4, hsample[0]); /* H factor */
    put_bits(pb, 4, vsample[0]); /* V factor */
    put_bits(pb, 8, 0); /* select matrix */

    /* Cb component */
    put_bits(pb, 8, 2); /* component number */
    put_bits(pb, 4, hsample[1]); /* H factor */
    put_bits(pb, 4, vsample[1]); /* V factor */
    put_bits(pb, 8, 0); /* select matrix */

    /* Cr component */
    put_bits(pb, 8, 3); /* component number */
    put_bits(pb, 4, hsample[2]); /* H factor */
    put_bits(pb, 4, vsample[2]); /* V factor */
    put_bits(pb, 8, 0); /* select matrix */

    /* scan header */
    put_marker(pb, SOS);
    put_bits(pb, 16, 12); /* length */
    put_bits(pb, 8, 3); /* 3 components */

    /* Y component */
    put_bits(pb, 8, 1); /* index */
    put_bits(pb, 4, 0); /* DC huffman table index */
    put_bits(pb, 4, 0); /* AC huffman table index */

    /* Cb component */
    put_bits(pb, 8, 2); /* index */
    put_bits(pb, 4, 1); /* DC huffman table index */
    put_bits(pb, 4, lossless ? 0 : 1); /* AC huffman table index */

    /* Cr component */
    put_bits(pb, 8, 3); /* index */
    put_bits(pb, 4, 1); /* DC huffman table index */
    put_bits(pb, 4, lossless ? 0 : 1); /* AC huffman table index */

    put_bits(pb, 8, lossless ? avctx->prediction_method + 1 : 0); /* Ss (not used) */

    switch (avctx->codec_id) {
    case AV_CODEC_ID_MJPEG:  put_bits(pb, 8, 63); break; /* Se (not used) */
    case AV_CODEC_ID_LJPEG:  put_bits(pb, 8,  0); break; /* not used */
    default: assert(0);
    }

    put_bits(pb, 8, 0); /* Ah/Al (not used) */
}

static void escape_FF(PutBitContext *pb, int start)
{
    int size = put_bits_count(pb) - start * 8;
    int i, ff_count;
    uint8_t *buf = pb->buf + start;
    int align= (-(size_t)(buf))&3;

    assert((size&7) == 0);
    size >>= 3;

    ff_count=0;
    for(i=0; i<size && i<align; i++){
        if(buf[i]==0xFF) ff_count++;
    }
    for(; i<size-15; i+=16){
        int acc, v;

        v= *(uint32_t*)(&buf[i]);
        acc= (((v & (v>>4))&0x0F0F0F0F)+0x01010101)&0x10101010;
        v= *(uint32_t*)(&buf[i+4]);
        acc+=(((v & (v>>4))&0x0F0F0F0F)+0x01010101)&0x10101010;
        v= *(uint32_t*)(&buf[i+8]);
        acc+=(((v & (v>>4))&0x0F0F0F0F)+0x01010101)&0x10101010;
        v= *(uint32_t*)(&buf[i+12]);
        acc+=(((v & (v>>4))&0x0F0F0F0F)+0x01010101)&0x10101010;

        acc>>=4;
        acc+= (acc>>16);
        acc+= (acc>>8);
        ff_count+= acc&0xFF;
    }
    for(; i<size; i++){
        if(buf[i]==0xFF) ff_count++;
    }

    if(ff_count==0) return;

    flush_put_bits(pb);
    skip_put_bytes(pb, ff_count);

    for(i=size-1; ff_count; i--){
        int v= buf[i];

        if(v==0xFF){
            buf[i+ff_count]= 0;
            ff_count--;
        }

        buf[i+ff_count]= v;
    }
}

void ff_mjpeg_encode_stuffing(PutBitContext * pbc)
{
    int length;
    length= (-put_bits_count(pbc))&7;
    if(length) put_bits(pbc, length, (1<<length)-1);
}

void ff_mjpeg_encode_picture_trailer(PutBitContext *pb, int header_bits)
{
    ff_mjpeg_encode_stuffing(pb);
    flush_put_bits(pb);

    assert((header_bits & 7) == 0);

    escape_FF(pb, header_bits >> 3);

    put_marker(pb, EOI);
}

void ff_mjpeg_encode_dc(PutBitContext *pb, int val,
                        uint8_t *huff_size, uint16_t *huff_code)
{
    int mant, nbits;

    if (val == 0) {
        put_bits(pb, huff_size[0], huff_code[0]);
    } else {
        mant = val;
        if (val < 0) {
            val = -val;
            mant--;
        }

        nbits= av_log2_16bit(val) + 1;

        put_bits(pb, huff_size[nbits], huff_code[nbits]);

        put_sbits(pb, nbits, mant);
    }
}