aac_parser.c File Reference

#include "parser.h"
#include "aac_ac3_parser.h"
#include "bitstream.h"
#include "mpeg4audio.h"

Go to the source code of this file.

Defines
#define	AAC_HEADER_SIZE   7
Functions
static int	aac_sync (uint64_t state, AACAC3ParseContext *hdr_info, int *need_next_header, int *new_frame_start)
static av_cold int	aac_parse_init (AVCodecParserContext *s1)
Variables
AVCodecParser	aac_parser

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Define Documentation

#define AAC_HEADER_SIZE   7

Definition at line 28 of file aac_parser.c.

Referenced by aac_parse_init(), and aac_sync().

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Function Documentation

static av_cold int aac_parse_init

(

AVCodecParserContext *

s1

)

[static]

Definition at line 76 of file aac_parser.c.

References AAC_HEADER_SIZE, aac_sync(), AACAC3ParseContext::header_size, s1, and AACAC3ParseContext::sync.

{
    AACAC3ParseContext *s = s1->priv_data;
    s->header_size = AAC_HEADER_SIZE;
    s->sync = aac_sync;
    return 0;
}

static int aac_sync	(	uint64_t	state,
		AACAC3ParseContext *	hdr_info,
		int *	need_next_header,
		int *	new_frame_start
	)			[static]

Definition at line 30 of file aac_parser.c.

References AAC_HEADER_SIZE, be2me_64, AACAC3ParseContext::bit_rate, bits, AACAC3ParseContext::channels, ff_mpeg4audio_channels, ff_mpeg4audio_sample_rates, get_bits(), init_get_bits(), AACAC3ParseContext::sample_rate, AACAC3ParseContext::samples, size, skip_bits(), and skip_bits1().

Referenced by aac_parse_init().

{
    GetBitContext bits;
    int size, rdb, ch, sr;
    uint64_t tmp = be2me_64(state);

    init_get_bits(&bits, ((uint8_t *)&tmp)+8-AAC_HEADER_SIZE, AAC_HEADER_SIZE * 8);

    if(get_bits(&bits, 12) != 0xfff)
        return 0;

    skip_bits1(&bits);          /* id */
    skip_bits(&bits, 2);        /* layer */
    skip_bits1(&bits);          /* protection_absent */
    skip_bits(&bits, 2);        /* profile_objecttype */
    sr = get_bits(&bits, 4);    /* sample_frequency_index */
    if(!ff_mpeg4audio_sample_rates[sr])
        return 0;
    skip_bits1(&bits);          /* private_bit */
    ch = get_bits(&bits, 3);    /* channel_configuration */
    if(!ff_mpeg4audio_channels[ch])
        return 0;
    skip_bits1(&bits);          /* original/copy */
    skip_bits1(&bits);          /* home */

    /* adts_variable_header */
    skip_bits1(&bits);          /* copyright_identification_bit */
    skip_bits1(&bits);          /* copyright_identification_start */
    size = get_bits(&bits, 13); /* aac_frame_length */
    if(size < AAC_HEADER_SIZE)
        return 0;

    skip_bits(&bits, 11);       /* adts_buffer_fullness */
    rdb = get_bits(&bits, 2);   /* number_of_raw_data_blocks_in_frame */

    hdr_info->channels = ff_mpeg4audio_channels[ch];
    hdr_info->sample_rate = ff_mpeg4audio_sample_rates[sr];
    hdr_info->samples = (rdb + 1) * 1024;
    hdr_info->bit_rate = size * 8 * hdr_info->sample_rate / hdr_info->samples;

    *need_next_header = 0;
    *new_frame_start  = 1;
    return size;
}

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Variable Documentation

AVCodecParser aac_parser

Initial value:

 {
    { CODEC_ID_AAC },
    sizeof(AACAC3ParseContext),
    aac_parse_init,
    ff_aac_ac3_parse,
    NULL,
}

Definition at line 85 of file aac_parser.c.

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