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ffmpeg / libavcodec / mjpeg2jpeg_bsf.c @ 2912e87a

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/*
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 * MJPEG/AVI1 to JPEG/JFIF bitstream format filter
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 * Copyright (c) 2010 Adrian Daerr and Nicolas George
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 *
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 * This file is part of Libav.
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 *
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 * Libav is free software; you can redistribute it and/or
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 * modify it under the terms of the GNU Lesser General Public
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 * License as published by the Free Software Foundation; either
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 * version 2.1 of the License, or (at your option) any later version.
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 *
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 * Libav is distributed in the hope that it will be useful,
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 * but WITHOUT ANY WARRANTY; without even the implied warranty of
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 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
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 * Lesser General Public License for more details.
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 *
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 * You should have received a copy of the GNU Lesser General Public
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 * License along with Libav; if not, write to the Free Software
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 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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 */
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/*
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 * Adapted from mjpeg2jpeg.c, with original copyright:
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 * Paris 2010 Adrian Daerr, public domain
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 */
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#include <string.h>
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#include "avcodec.h"
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#include "mjpeg.h"
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static const uint8_t jpeg_header[] = {
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    0xff, 0xd8,                     // SOI
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    0xff, 0xe0,                     // APP0
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    0x00, 0x10,                     // APP0 header size (including
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                                    // this field, but excluding preceding)
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    0x4a, 0x46, 0x49, 0x46, 0x00,   // ID string 'JFIF\0'
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    0x01, 0x01,                     // version
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    0x00,                           // bits per type
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    0x00, 0x00,                     // X density
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    0x00, 0x00,                     // Y density
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    0x00,                           // X thumbnail size
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    0x00,                           // Y thumbnail size
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};
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static const int dht_segment_size = 420;
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static const uint8_t dht_segment_head[] = { 0xFF, 0xC4, 0x01, 0xA2, 0x00 };
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static const uint8_t dht_segment_frag[] = {
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    0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09,
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    0x0a, 0x0b, 0x01, 0x00, 0x03, 0x01, 0x01, 0x01, 0x01, 0x01,
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    0x01, 0x01, 0x01, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00,
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};
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static uint8_t *append(uint8_t *buf, const uint8_t *src, int size)
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{
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    memcpy(buf, src, size);
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    return buf + size;
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}
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static uint8_t *append_dht_segment(uint8_t *buf)
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{
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    buf = append(buf, dht_segment_head, sizeof(dht_segment_head));
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    buf = append(buf, ff_mjpeg_bits_dc_luminance + 1, 16);
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    buf = append(buf, dht_segment_frag, sizeof(dht_segment_frag));
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    buf = append(buf, ff_mjpeg_val_dc, 12);
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    *(buf++) = 0x10;
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    buf = append(buf, ff_mjpeg_bits_ac_luminance + 1, 16);
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    buf = append(buf, ff_mjpeg_val_ac_luminance, 162);
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    *(buf++) = 0x11;
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    buf = append(buf, ff_mjpeg_bits_ac_chrominance + 1, 16);
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    buf = append(buf, ff_mjpeg_val_ac_chrominance, 162);
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    return buf;
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}
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static int mjpeg2jpeg_filter(AVBitStreamFilterContext *bsfc,
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                             AVCodecContext *avctx, const char *args,
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                             uint8_t **poutbuf, int *poutbuf_size,
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                             const uint8_t *buf, int buf_size,
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                             int keyframe)
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{
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    int input_skip, output_size;
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    uint8_t *output, *out;
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    if (buf_size < 12) {
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        av_log(avctx, AV_LOG_ERROR, "input is truncated\n");
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        return AVERROR_INVALIDDATA;
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    }
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    if (memcmp("AVI1", buf + 6, 4)) {
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        av_log(avctx, AV_LOG_ERROR, "input is not MJPEG/AVI1\n");
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        return AVERROR_INVALIDDATA;
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    }
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    input_skip = (buf[4] << 8) + buf[5] + 4;
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    if (buf_size < input_skip) {
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        av_log(avctx, AV_LOG_ERROR, "input is truncated\n");
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        return AVERROR_INVALIDDATA;
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    }
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    output_size = buf_size - input_skip +
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                  sizeof(jpeg_header) + dht_segment_size;
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    output = out = av_malloc(output_size);
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    if (!output)
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        return AVERROR(ENOMEM);
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    out = append(out, jpeg_header, sizeof(jpeg_header));
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    out = append_dht_segment(out);
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    out = append(out, buf + input_skip, buf_size - input_skip);
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    *poutbuf = output;
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    *poutbuf_size = output_size;
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    return 1;
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}
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AVBitStreamFilter ff_mjpeg2jpeg_bsf = {
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    .name           = "mjpeg2jpeg",
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    .priv_data_size = 0,
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    .filter         = mjpeg2jpeg_filter,
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};