143 lines
		
	
	
		
			4.4 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			143 lines
		
	
	
		
			4.4 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
| /*
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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 FFmpeg.
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|  *
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|  * FFmpeg 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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|  * FFmpeg 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 FFmpeg; 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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| /*
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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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| 
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| #include <string.h>
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| 
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| #include "libavutil/error.h"
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| #include "libavutil/intreadwrite.h"
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| 
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| #include "bsf.h"
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| #include "bsf_internal.h"
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| #include "jpegtables.h"
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| #include "mjpeg.h"
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| 
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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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| 
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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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| 
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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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| 
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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, avpriv_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, avpriv_mjpeg_val_dc, 12);
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|     *(buf++) = 0x10;
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|     buf = append(buf, avpriv_mjpeg_bits_ac_luminance + 1, 16);
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|     buf = append(buf, avpriv_mjpeg_val_ac_luminance, 162);
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|     *(buf++) = 0x11;
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|     buf = append(buf, avpriv_mjpeg_bits_ac_chrominance + 1, 16);
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|     buf = append(buf, avpriv_mjpeg_val_ac_chrominance, 162);
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|     return buf;
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| }
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| 
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| static int mjpeg2jpeg_filter(AVBSFContext *ctx, AVPacket *out)
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| {
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|     AVPacket *in;
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|     int ret = 0;
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|     int input_skip, output_size;
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|     uint8_t *output;
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| 
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|     ret = ff_bsf_get_packet(ctx, &in);
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|     if (ret < 0)
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|         return ret;
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| 
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|     if (in->size < 12) {
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|         av_log(ctx, AV_LOG_ERROR, "input is truncated\n");
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|         ret = AVERROR_INVALIDDATA;
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|         goto fail;
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|     }
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|     if (AV_RB16(in->data) != 0xffd8) {
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|         av_log(ctx, AV_LOG_ERROR, "input is not MJPEG\n");
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|         ret = AVERROR_INVALIDDATA;
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|         goto fail;
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|     }
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|     if (in->data[2] == 0xff && in->data[3] == APP0) {
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|         input_skip = (in->data[4] << 8) + in->data[5] + 4;
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|     } else {
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|         input_skip = 2;
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|     }
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|     if (in->size < input_skip) {
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|         av_log(ctx, AV_LOG_ERROR, "input is truncated\n");
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|         ret = AVERROR_INVALIDDATA;
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|         goto fail;
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|     }
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|     output_size = in->size - input_skip +
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|                   sizeof(jpeg_header) + dht_segment_size;
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|     ret = av_new_packet(out, output_size);
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|     if (ret < 0)
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|         goto fail;
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| 
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|     output = out->data;
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| 
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|     output = append(output, jpeg_header, sizeof(jpeg_header));
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|     output = append_dht_segment(output);
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|     output = append(output, in->data + input_skip, in->size - input_skip);
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| 
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|     ret = av_packet_copy_props(out, in);
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|     if (ret < 0)
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|         goto fail;
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| 
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| fail:
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|     if (ret < 0)
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|         av_packet_unref(out);
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|     av_packet_free(&in);
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|     return ret;
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| }
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| 
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| static const enum AVCodecID codec_ids[] = {
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|     AV_CODEC_ID_MJPEG, AV_CODEC_ID_NONE,
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| };
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| 
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| const AVBitStreamFilter ff_mjpeg2jpeg_bsf = {
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|     .name           = "mjpeg2jpeg",
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|     .filter         = mjpeg2jpeg_filter,
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|     .codec_ids      = codec_ids,
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| };
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