ffmpeg/libav/au.c

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/*
* AU encoder and decoder
* Copyright (c) 2001 Fabrice Bellard.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
/*
* First version by Francois Revol revol@free.fr
*
* Reference documents:
* http://www.opengroup.org/public/pubs/external/auformat.html
* http://www.goice.co.jp/member/mo/formats/au.html
*/
#include "avformat.h"
#include "avi.h"
/* if we don't know the size in advance */
#define AU_UNKOWN_SIZE ((UINT32)(~0))
/* The ffmpeg codecs we support, and the IDs they have in the file */
CodecTag codec_au_tags[] = {
{ CODEC_ID_PCM_MULAW, 1 },
{ CODEC_ID_PCM_S16BE, 3 },
{ CODEC_ID_PCM_ALAW, 27 },
{ 0, 0 },
};
/* AUDIO_FILE header */
int put_au_header(ByteIOContext *pb, AVCodecContext *enc)
{
int tag;
tag = codec_get_tag(codec_au_tags, enc->codec_id);
if (tag == 0)
return -1;
put_tag(pb, ".snd"); /* magic number */
put_be32(pb, 24); /* header size */
put_be32(pb, AU_UNKOWN_SIZE); /* data size */
put_be32(pb, (UINT32)tag); /* codec ID */
put_be32(pb, enc->sample_rate);
put_be32(pb, (UINT32)enc->channels);
return 0;
}
static int au_write_header(AVFormatContext *s)
{
ByteIOContext *pb = &s->pb;
s->priv_data = NULL;
/* format header */
if (put_au_header(pb, &s->streams[0]->codec) < 0) {
return -1;
}
put_flush_packet(pb);
return 0;
}
static int au_write_packet(AVFormatContext *s, int stream_index_ptr,
UINT8 *buf, int size, int force_pts)
{
ByteIOContext *pb = &s->pb;
put_buffer(pb, buf, size);
return 0;
}
static int au_write_trailer(AVFormatContext *s)
{
ByteIOContext *pb = &s->pb;
offset_t file_size;
if (!url_is_streamed(&s->pb)) {
/* update file size */
file_size = url_ftell(pb);
url_fseek(pb, 8, SEEK_SET);
put_be32(pb, (UINT32)(file_size - 24));
url_fseek(pb, file_size, SEEK_SET);
put_flush_packet(pb);
}
return 0;
}
static int au_probe(AVProbeData *p)
{
/* check file header */
if (p->buf_size <= 24)
return 0;
if (p->buf[0] == '.' && p->buf[1] == 's' &&
p->buf[2] == 'n' && p->buf[3] == 'd')
return AVPROBE_SCORE_MAX;
else
return 0;
}
/* au input */
static int au_read_header(AVFormatContext *s,
AVFormatParameters *ap)
{
int size;
unsigned int tag;
ByteIOContext *pb = &s->pb;
unsigned int id, codec, channels, rate;
AVStream *st;
/* check ".snd" header */
tag = get_le32(pb);
if (tag != MKTAG('.', 's', 'n', 'd'))
return -1;
size = get_be32(pb); /* header size */
get_be32(pb); /* data size */
id = get_be32(pb);
rate = get_be32(pb);
channels = get_be32(pb);
codec = codec_get_id(codec_au_tags, id);
if (size >= 24) {
/* skip unused data */
url_fseek(pb, size - 24, SEEK_CUR);
}
/* now we are ready: build format streams */
st = av_malloc(sizeof(AVStream));
if (!st)
return -1;
s->nb_streams = 1;
s->streams[0] = st;
st->id = 0;
st->codec.codec_type = CODEC_TYPE_AUDIO;
st->codec.codec_tag = id;
st->codec.codec_id = codec;
st->codec.channels = channels;
st->codec.sample_rate = rate;
return 0;
}
#define MAX_SIZE 4096
static int au_read_packet(AVFormatContext *s,
AVPacket *pkt)
{
int packet_size, n, ret;
if (url_feof(&s->pb))
return -EIO;
packet_size = url_get_packet_size(&s->pb);
n = MAX_SIZE / packet_size;
if (n <= 0)
return n = 1;
if (av_new_packet(pkt, n * packet_size))
return -EIO;
pkt->stream_index = 0;
ret = get_buffer(&s->pb, pkt->data, pkt->size);
if (ret < 0)
av_free_packet(pkt);
/* note: we need to modify the packet size here to handle the last
packet */
pkt->size = ret;
return ret;
}
static int au_read_close(AVFormatContext *s)
{
return 0;
}
static AVInputFormat au_iformat = {
"au",
"SUN AU Format",
0,
au_probe,
au_read_header,
au_read_packet,
au_read_close,
};
static AVOutputFormat au_oformat = {
"au",
"SUN AU Format",
"audio/basic",
"au",
0,
CODEC_ID_PCM_S16BE,
CODEC_ID_NONE,
au_write_header,
au_write_packet,
au_write_trailer,
};
int au_init(void)
{
av_register_input_format(&au_iformat);
av_register_output_format(&au_oformat);
return 0;
}