adtsenc.c File Reference

#include "libavcodec/bitstream.h"
#include "avformat.h"

Go to the source code of this file.

Data Structures
struct	ADTSContext
Defines
#define	ADTS_HEADER_SIZE   7
Functions
static int	decode_extradata (ADTSContext *adts, uint8_t *buf, int size)
static int	adts_write_header (AVFormatContext *s)
static int	adts_write_frame_header (AVFormatContext *s, int size)
static int	adts_write_packet (AVFormatContext *s, AVPacket *pkt)
Variables
AVOutputFormat	adts_muxer

---

Define Documentation

#define ADTS_HEADER_SIZE   7

Definition at line 26 of file adtsenc.c.

Referenced by adts_write_frame_header().

---

Function Documentation

static int adts_write_frame_header	(	AVFormatContext *	s,
		int	size
	)			[static]

Definition at line 60 of file adtsenc.c.

References ADTS_HEADER_SIZE, ADTSContext::channel_conf, flush_put_bits(), init_put_bits(), ADTSContext::objecttype, AVFormatContext::pb, AVFormatContext::priv_data, put_bits(), put_buffer(), and ADTSContext::sample_rate_index.

Referenced by adts_write_packet().

{
    ADTSContext *ctx = s->priv_data;
    PutBitContext pb;
    uint8_t buf[ADTS_HEADER_SIZE];

    init_put_bits(&pb, buf, ADTS_HEADER_SIZE);

    /* adts_fixed_header */
    put_bits(&pb, 12, 0xfff);   /* syncword */
    put_bits(&pb, 1, 0);        /* ID */
    put_bits(&pb, 2, 0);        /* layer */
    put_bits(&pb, 1, 1);        /* protection_absent */
    put_bits(&pb, 2, ctx->objecttype); /* profile_objecttype */
    put_bits(&pb, 4, ctx->sample_rate_index);
    put_bits(&pb, 1, 0);        /* private_bit */
    put_bits(&pb, 3, ctx->channel_conf); /* channel_configuration */
    put_bits(&pb, 1, 0);        /* original_copy */
    put_bits(&pb, 1, 0);        /* home */

    /* adts_variable_header */
    put_bits(&pb, 1, 0);        /* copyright_identification_bit */
    put_bits(&pb, 1, 0);        /* copyright_identification_start */
    put_bits(&pb, 13, ADTS_HEADER_SIZE + size); /* aac_frame_length */
    put_bits(&pb, 11, 0x7ff);   /* adts_buffer_fullness */
    put_bits(&pb, 2, 0);        /* number_of_raw_data_blocks_in_frame */

    flush_put_bits(&pb);
    put_buffer(s->pb, buf, ADTS_HEADER_SIZE);

    return 0;
}

static int adts_write_header

(

AVFormatContext *

s

)

[static]

Definition at line 49 of file adtsenc.c.

References AVStream::codec, decode_extradata(), AVCodecContext::extradata, AVCodecContext::extradata_size, AVFormatContext::priv_data, and AVFormatContext::streams.

{
    ADTSContext *adts = s->priv_data;
    AVCodecContext *avc = s->streams[0]->codec;

    if(avc->extradata_size > 0)
        decode_extradata(adts, avc->extradata, avc->extradata_size);

    return 0;
}

static int adts_write_packet	(	AVFormatContext *	s,
		AVPacket *	pkt
	)			[static]

Definition at line 93 of file adtsenc.c.

References adts_write_frame_header(), AVPacket::data, AVFormatContext::pb, AVFormatContext::priv_data, put_buffer(), put_flush_packet(), AVPacket::size, and ADTSContext::write_adts.

{
    ADTSContext *adts = s->priv_data;
    ByteIOContext *pb = s->pb;

    if (!pkt->size)
        return 0;
    if(adts->write_adts)
        adts_write_frame_header(s, pkt->size);
    put_buffer(pb, pkt->data, pkt->size);
    put_flush_packet(pb);

    return 0;
}

static int decode_extradata	(	ADTSContext *	adts,
		uint8_t *	buf,
		int	size
	)			[static]

Definition at line 35 of file adtsenc.c.

References ADTSContext::channel_conf, get_bits(), init_get_bits(), ADTSContext::objecttype, ADTSContext::sample_rate_index, and ADTSContext::write_adts.

Referenced by adts_write_header().

{
    GetBitContext gb;

    init_get_bits(&gb, buf, size * 8);
    adts->objecttype = get_bits(&gb, 5) - 1;
    adts->sample_rate_index = get_bits(&gb, 4);
    adts->channel_conf = get_bits(&gb, 4);

    adts->write_adts = 1;

    return 0;
}

---

Variable Documentation

AVOutputFormat adts_muxer

Initial value:

 {
    "adts",
    NULL_IF_CONFIG_SMALL("ADTS AAC"),
    "audio/aac",
    "aac",
    sizeof(ADTSContext),
    CODEC_ID_AAC,
    CODEC_ID_NONE,
    adts_write_header,
    adts_write_packet,
}

Definition at line 108 of file adtsenc.c.

---