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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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* This file is part of Libav.
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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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* 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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* 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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* Adapted from mjpeg2jpeg.c, with original copyright:
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* Paris 2010 Adrian Daerr, public domain
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static const uint8_t jpeg_header[] = {
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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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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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static uint8_t *append(uint8_t *buf, const uint8_t *src, int size)
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memcpy(buf, src, size);
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static uint8_t *append_dht_segment(uint8_t *buf)
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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 = 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 = 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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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 input_skip, output_size;
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uint8_t *output, *out;
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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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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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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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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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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_size = output_size;
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AVBitStreamFilter ff_mjpeg2jpeg_bsf = {
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.name = "mjpeg2jpeg",
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.filter = mjpeg2jpeg_filter,