amr.c File Reference

#include "avformat.h"

Go to the source code of this file.

Functions
static int	amr_probe (AVProbeData *p)
static int	amr_read_header (AVFormatContext *s, AVFormatParameters *ap)
static int	amr_read_packet (AVFormatContext *s, AVPacket *pkt)
Variables
static const char	AMR_header [] = "#!AMR\n"
static const char	AMRWB_header [] = "#!AMR-WB\n"

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Function Documentation

static int amr_probe

(

AVProbeData *

p

)

[static]

Definition at line 65 of file amr.c.

References AMR_header, AVPROBE_SCORE_MAX, and AVProbeData::buf.

{
    //Only check for "#!AMR" which could be amr-wb, amr-nb.
    //This will also trigger multichannel files: "#!AMR_MC1.0\n" and
    //"#!AMR-WB_MC1.0\n" (not supported)

    if(memcmp(p->buf,AMR_header,5)==0)
        return AVPROBE_SCORE_MAX;
    else
        return 0;
}

static int amr_read_header	(	AVFormatContext *	s,
		AVFormatParameters *	ap
	)			[static]

Definition at line 78 of file amr.c.

References AMR_header, AMRWB_header, av_new_stream(), av_set_pts_info(), AVERROR, AVCodecContext::channels, AVStream::codec, AVCodecContext::codec_id, CODEC_ID_AMR_NB, CODEC_ID_AMR_WB, AVCodecContext::codec_tag, AVCodecContext::codec_type, CODEC_TYPE_AUDIO, get_buffer(), MKTAG, AVFormatContext::pb, and AVCodecContext::sample_rate.

{
    ByteIOContext *pb = s->pb;
    AVStream *st;
    uint8_t header[9];

    get_buffer(pb, header, 6);

    st = av_new_stream(s, 0);
    if (!st)
    {
        return AVERROR(ENOMEM);
    }
    if(memcmp(header,AMR_header,6)!=0)
    {
        get_buffer(pb, header+6, 3);
        if(memcmp(header,AMRWB_header,9)!=0)
        {
            return -1;
        }

        st->codec->codec_tag = MKTAG('s', 'a', 'w', 'b');
        st->codec->codec_id = CODEC_ID_AMR_WB;
        st->codec->sample_rate = 16000;
    }
    else
    {
        st->codec->codec_tag = MKTAG('s', 'a', 'm', 'r');
        st->codec->codec_id = CODEC_ID_AMR_NB;
        st->codec->sample_rate = 8000;
    }
    st->codec->channels = 1;
    st->codec->codec_type = CODEC_TYPE_AUDIO;
    av_set_pts_info(st, 64, 1, st->codec->sample_rate);

    return 0;
}

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

Definition at line 117 of file amr.c.

References av_free_packet(), av_new_packet(), AVERROR, AVStream::codec, AVCodecContext::codec_id, CODEC_ID_AMR_NB, CODEC_ID_AMR_WB, AVPacket::data, AVPacket::duration, get_buffer(), get_byte(), AVFormatContext::pb, AVPacket::pos, size, AVPacket::stream_index, AVFormatContext::streams, url_feof(), and url_ftell().

{
    AVCodecContext *enc = s->streams[0]->codec;
    int read, size = 0, toc, mode;

    if (url_feof(s->pb))
    {
        return AVERROR(EIO);
    }

//FIXME this is wrong, this should rather be in a AVParset
    toc=get_byte(s->pb);
    mode = (toc >> 3) & 0x0F;

    if (enc->codec_id == CODEC_ID_AMR_NB)
    {
        static const uint8_t packed_size[16] = {12, 13, 15, 17, 19, 20, 26, 31, 5, 0, 0, 0, 0, 0, 0, 0};

        size=packed_size[mode]+1;
    }
    else if(enc->codec_id == CODEC_ID_AMR_WB)
    {
        static uint8_t packed_size[16] = {18, 24, 33, 37, 41, 47, 51, 59, 61, 6, 6, 0, 0, 0, 1, 1};

        size=packed_size[mode];
    }
    else
    {
        assert(0);
    }

    if ( (size==0) || av_new_packet(pkt, size))
    {
        return AVERROR(EIO);
    }

    pkt->stream_index = 0;
    pkt->pos= url_ftell(s->pb);
    pkt->data[0]=toc;
    pkt->duration= enc->codec_id == CODEC_ID_AMR_NB ? 160 : 320;
    read = get_buffer(s->pb, pkt->data+1, size-1);

    if (read != size-1)
    {
        av_free_packet(pkt);
        return AVERROR(EIO);
    }

    return 0;
}

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Variable Documentation

const char AMR_header[] = "#!AMR\n" [static]

Definition at line 30 of file amr.c.

Referenced by amr_probe(), and amr_read_header().

const char AMRWB_header[] = "#!AMR-WB\n" [static]

Definition at line 31 of file amr.c.

Referenced by amr_read_header().

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