/*

 * MJPEG/AVI1 to JPEG/JFIF bitstream format filter

 * Copyright (c) 2010 Adrian Daerr and Nicolas George

 *

 * 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

 * 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 FFmpeg; if not, write to the Free Software

 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

 */

/*

 * Adapted from mjpeg2jpeg.c, with original copyright:

 * Paris 2010 Adrian Daerr, public domain

 */

#include <string.h>

#include "libavutil/error.h"

#include "libavutil/intreadwrite.h"

#include "bsf.h"

#include "bsf_internal.h"

#include "jpegtables.h"

#include "mjpeg.h"

static const uint8_t jpeg_header[] = {

    0xff, 0xd8,                     // SOI

    0xff, 0xe0,                     // APP0

    0x00, 0x10,                     // APP0 header size (including

                                    // this field, but excluding preceding)

    0x4a, 0x46, 0x49, 0x46, 0x00,   // ID string 'JFIF\0'

    0x01, 0x01,                     // version

    0x00,                           // bits per type

    0x00, 0x00,                     // X density

    0x00, 0x00,                     // Y density

    0x00,                           // X thumbnail size

    0x00,                           // Y thumbnail size

};

static const int dht_segment_size = 420;

static const uint8_t dht_segment_head[] = { 0xFF, 0xC4, 0x01, 0xA2, 0x00 };

static const uint8_t dht_segment_frag[] = {

    0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09,

    0x0a, 0x0b, 0x01, 0x00, 0x03, 0x01, 0x01, 0x01, 0x01, 0x01,

    0x01, 0x01, 0x01, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00,

};

static uint8_t *append(uint8_t *buf, const uint8_t *src, int size)

{

    memcpy(buf, src, size);

    return buf + size;

}

static uint8_t *append_dht_segment(uint8_t *buf)

{

    buf = append(buf, dht_segment_head, sizeof(dht_segment_head));

    buf = append(buf, ff_mjpeg_bits_dc_luminance + 1, 16);

    buf = append(buf, dht_segment_frag, sizeof(dht_segment_frag));

    buf = append(buf, ff_mjpeg_val_dc, 12);

    *(buf++) = 0x10;

    buf = append(buf, ff_mjpeg_bits_ac_luminance + 1, 16);

    buf = append(buf, ff_mjpeg_val_ac_luminance, 162);

    *(buf++) = 0x11;

    buf = append(buf, ff_mjpeg_bits_ac_chrominance + 1, 16);

    buf = append(buf, ff_mjpeg_val_ac_chrominance, 162);

    return buf;

}

static int mjpeg2jpeg_filter(AVBSFContext *ctx, AVPacket *out)

{

    AVPacket *in;

    int ret = 0;

    int input_skip, output_size;

    uint8_t *output;

    ret = ff_bsf_get_packet(ctx, &in);

    if (ret < 0)

        return ret;

    if (in->size < 12) {

        av_log(ctx, AV_LOG_ERROR, "input is truncated\n");

        ret = AVERROR_INVALIDDATA;

        goto fail;

    }

    if (AV_RB16(in->data) != 0xffd8) {

        av_log(ctx, AV_LOG_ERROR, "input is not MJPEG\n");

        ret = AVERROR_INVALIDDATA;

        goto fail;

    }

    if (in->data[2] == 0xff && in->data[3] == APP0) {

        input_skip = (in->data[4] << 8) + in->data[5] + 4;

    } else {

        input_skip = 2;

    }

    if (in->size < input_skip) {

        av_log(ctx, AV_LOG_ERROR, "input is truncated\n");

        ret = AVERROR_INVALIDDATA;

        goto fail;

    }

    output_size = in->size - input_skip +

                  sizeof(jpeg_header) + dht_segment_size;

    ret = av_new_packet(out, output_size);

    if (ret < 0)

        goto fail;

    output = out->data;

    output = append(output, jpeg_header, sizeof(jpeg_header));

    output = append_dht_segment(output);

    output = append(output, in->data + input_skip, in->size - input_skip);

    ret = av_packet_copy_props(out, in);

    if (ret < 0)

        goto fail;

fail:

    if (ret < 0)

        av_packet_unref(out);

    av_packet_free(&in);

    return ret;

}

static const enum AVCodecID codec_ids[] = {

    AV_CODEC_ID_MJPEG, AV_CODEC_ID_NONE,

};

const FFBitStreamFilter ff_mjpeg2jpeg_bsf = {

    .p.name         = "mjpeg2jpeg",

    .p.codec_ids    = codec_ids,

    .filter         = mjpeg2jpeg_filter,

};