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			109 lines
		
	
	
		
			3.6 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			109 lines
		
	
	
		
			3.6 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
| /*
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|  * MJPEG A dump header bitstream filter
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|  * Copyright (c) 2006 Baptiste Coudurier
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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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|  * @file
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|  * MJPEG A dump header bitstream filter
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|  * modifies bitstream to be decoded by quicktime
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|  */
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| 
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| #include "bsf.h"
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| #include "bsf_internal.h"
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| #include "bytestream.h"
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| #include "mjpeg.h"
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| 
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| 
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| static int mjpega_dump_header(AVBSFContext *ctx, AVPacket *out)
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| {
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|     AVPacket *in;
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|     uint8_t *out_buf;
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|     unsigned dqt = 0, dht = 0, sof0 = 0;
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|     int ret = 0, i;
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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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|     ret = av_new_packet(out, in->size + 44);
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|     if (ret < 0)
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|         goto fail;
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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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|     out_buf = out->data;
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|     bytestream_put_byte(&out_buf, 0xff);
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|     bytestream_put_byte(&out_buf, SOI);
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|     bytestream_put_byte(&out_buf, 0xff);
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|     bytestream_put_byte(&out_buf, APP1);
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|     bytestream_put_be16(&out_buf, 42); /* size */
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|     bytestream_put_be32(&out_buf, 0);
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|     bytestream_put_buffer(&out_buf, "mjpg", 4);
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|     bytestream_put_be32(&out_buf, in->size + 44); /* field size */
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|     bytestream_put_be32(&out_buf, in->size + 44); /* pad field size */
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|     bytestream_put_be32(&out_buf, 0);             /* next ptr */
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| 
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|     for (i = 0; i < in->size - 1; i++) {
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|         if (in->data[i] == 0xff) {
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|             switch (in->data[i + 1]) {
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|             case DQT:  dqt  = i + 46; break;
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|             case DHT:  dht  = i + 46; break;
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|             case SOF0: sof0 = i + 46; break;
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|             case SOS:
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|                 bytestream_put_be32(&out_buf, dqt); /* quant off */
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|                 bytestream_put_be32(&out_buf, dht); /* huff off */
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|                 bytestream_put_be32(&out_buf, sof0); /* image off */
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|                 bytestream_put_be32(&out_buf, i + 46); /* scan off */
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|                 bytestream_put_be32(&out_buf, i + 46 + AV_RB16(in->data + i + 2)); /* data off */
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|                 bytestream_put_buffer(&out_buf, in->data + 2, in->size - 2); /* skip already written SOI */
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| 
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|                 out->size = out_buf - out->data;
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|                 av_packet_free(&in);
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|                 return 0;
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|             case APP1:
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|                 if (i + 8 < in->size && AV_RL32(in->data + i + 8) == AV_RL32("mjpg")) {
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|                     av_log(ctx, AV_LOG_ERROR, "bitstream already formatted\n");
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|                     av_packet_unref(out);
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|                     av_packet_move_ref(out, in);
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|                     av_packet_free(&in);
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|                     return 0;
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|                 }
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|             }
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|         }
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|     }
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|     av_log(ctx, AV_LOG_ERROR, "could not find SOS marker in bitstream\n");
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| fail:
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|     av_packet_unref(out);
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|     av_packet_free(&in);
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|     return AVERROR_INVALIDDATA;
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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_mjpega_dump_header_bsf = {
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|     .name      = "mjpegadump",
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|     .filter    = mjpega_dump_header,
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|     .codec_ids = codec_ids,
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| };
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