It more directly shows that ff_flac_decode_frame_header() does not modify the AVCodecContext given to it at all; and it would not be allowed to do so, given that it is used by the parser when it is still unknown whether said frame header is even valid. Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
		
			
				
	
	
		
			90 lines
		
	
	
		
			3.7 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			90 lines
		
	
	
		
			3.7 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
| /*
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|  * FLAC (Free Lossless Audio Codec) decoder/parser common functions
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|  * Copyright (c) 2008 Justin Ruggles
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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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|  * FLAC (Free Lossless Audio Codec) decoder/parser common functions
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|  */
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| 
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| #ifndef AVCODEC_FLAC_PARSE_H
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| #define AVCODEC_FLAC_PARSE_H
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| 
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| #include "avcodec.h"
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| #include "get_bits.h"
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| 
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| typedef struct FLACStreaminfo {
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|     int samplerate;         /**< sample rate                             */
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|     int channels;           /**< number of channels                      */
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|     int bps;                /**< bits-per-sample                         */
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|     int max_blocksize;      /**< maximum block size, in samples          */
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|     int max_framesize;      /**< maximum frame size, in bytes            */
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|     int64_t samples;        /**< total number of samples                 */
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| } FLACStreaminfo;
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| 
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| typedef struct FLACFrameInfo {
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|     int samplerate;         /**< sample rate                             */
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|     int channels;           /**< number of channels                      */
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|     int bps;                /**< bits-per-sample                         */
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|     int blocksize;          /**< block size of the frame                 */
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|     int ch_mode;            /**< channel decorrelation mode              */
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|     int64_t frame_or_sample_num;    /**< frame number or sample number   */
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|     int is_var_size;                /**< specifies if the stream uses variable
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|                                          block sizes or a fixed block size;
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|                                          also determines the meaning of
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|                                          frame_or_sample_num             */
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| } FLACFrameInfo;
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| 
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| /**
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|  * Parse the Streaminfo metadata block
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|  * @param[out] avctx   codec context to set basic stream parameters
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|  * @param[out] s       where parsed information is stored
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|  * @param[in]  buffer  pointer to start of 34-byte streaminfo data
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|  *
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|  * @return negative error code on faiure or >= 0 on success
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|  */
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| int ff_flac_parse_streaminfo(AVCodecContext *avctx, struct FLACStreaminfo *s,
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|                               const uint8_t *buffer);
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| 
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| /**
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|  * Validate the FLAC extradata.
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|  * @param[in]  avctx codec context containing the extradata.
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|  * @param[out] format extradata format.
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|  * @param[out] streaminfo_start pointer to start of 34-byte STREAMINFO data.
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|  * @return 1 if valid, 0 if not valid.
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|  */
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| int ff_flac_is_extradata_valid(AVCodecContext *avctx,
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|                                uint8_t **streaminfo_start);
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| 
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| /**
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|  * Validate and decode a frame header.
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|  * @param      logctx context for logging
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|  * @param      gb    GetBitContext from which to read frame header
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|  * @param[out] fi    frame information
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|  * @param      log_level_offset  log level offset. can be used to silence error messages.
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|  * @return non-zero on error, 0 if ok
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|  */
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| int ff_flac_decode_frame_header(void *logctx, GetBitContext *gb,
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|                                 FLACFrameInfo *fi, int log_level_offset);
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| 
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| void ff_flac_set_channel_layout(AVCodecContext *avctx, int channels);
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| 
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| #endif /* AVCODEC_FLAC_PARSE_H */
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