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ffmpeg/libav/wav.c

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/*
* WAV 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
*/
#include "avformat.h"
#include "avi.h"
CodecTag codec_wav_tags[] = {
{ CODEC_ID_MP2, 0x50 },
{ CODEC_ID_MP3LAME, 0x55 },
{ CODEC_ID_AC3, 0x2000 },
{ CODEC_ID_PCM_S16LE, 0x01 },
{ CODEC_ID_PCM_U8, 0x01 }, /* must come after s16le in this list */
{ CODEC_ID_PCM_ALAW, 0x06 },
{ CODEC_ID_PCM_MULAW, 0x07 },
{ 0, 0 },
};
/* WAVEFORMATEX header */
/* returns the size or -1 on error */
int put_wav_header(ByteIOContext *pb, AVCodecContext *enc)
{
int tag, bps, blkalign, bytespersec;
int hdrsize = 18;
tag = codec_get_tag(codec_wav_tags, enc->codec_id);
if (tag == 0)
return -1;
put_le16(pb, tag);
put_le16(pb, enc->channels);
put_le32(pb, enc->sample_rate);
if (enc->codec_id == CODEC_ID_PCM_U8 ||
enc->codec_id == CODEC_ID_PCM_ALAW ||
enc->codec_id == CODEC_ID_PCM_MULAW) {
bps = 8;
} else if (enc->codec_id == CODEC_ID_MP2 || enc->codec_id == CODEC_ID_MP3LAME) {
bps = 0;
} else {
bps = 16;
}
if (enc->codec_id == CODEC_ID_MP2 || enc->codec_id == CODEC_ID_MP3LAME) {
blkalign = 1;
//blkalign = 144 * enc->bit_rate/enc->sample_rate;
} else
blkalign = enc->channels*bps >> 3;
if (enc->codec_id == CODEC_ID_PCM_U8 ||
enc->codec_id == CODEC_ID_PCM_S16LE) {
bytespersec = enc->sample_rate * blkalign;
} else {
bytespersec = enc->bit_rate / 8;
}
put_le32(pb, bytespersec); /* bytes per second */
put_le16(pb, blkalign); /* block align */
put_le16(pb, bps); /* bits per sample */
if (enc->codec_id == CODEC_ID_MP3LAME) {
put_le16(pb, 12); /* wav_extra_size */
hdrsize += 12;
put_le16(pb, 1); /* wID */
put_le32(pb, 2); /* fdwFlags */
put_le16(pb, 1152); /* nBlockSize */
put_le16(pb, 1); /* nFramesPerBlock */
put_le16(pb, 1393); /* nCodecDelay */
} else if (enc->codec_id == CODEC_ID_MP2) {
put_le16(pb, 22); /* wav_extra_size */
hdrsize += 22;
put_le16(pb, 2); /* fwHeadLayer */
put_le32(pb, enc->bit_rate); /* dwHeadBitrate */
put_le16(pb, enc->channels == 2 ? 1 : 8); /* fwHeadMode */
put_le16(pb, 0); /* fwHeadModeExt */
put_le16(pb, 1); /* wHeadEmphasis */
put_le16(pb, 16); /* fwHeadFlags */
put_le32(pb, 0); /* dwPTSLow */
put_le32(pb, 0); /* dwPTSHigh */
} else
put_le16(pb, 0); /* wav_extra_size */
return hdrsize;
}
int wav_codec_get_id(unsigned int tag, int bps)
{
int id;
id = codec_get_id(codec_wav_tags, tag);
if (id <= 0)
return id;
/* handle specific u8 codec */
if (id == CODEC_ID_PCM_S16LE && bps == 8)
id = CODEC_ID_PCM_U8;
return id;
}
typedef struct {
offset_t data;
} WAVContext;
static int wav_write_header(AVFormatContext *s)
{
WAVContext *wav = s->priv_data;
ByteIOContext *pb = &s->pb;
offset_t fmt;
put_tag(pb, "RIFF");
put_le32(pb, 0); /* file length */
put_tag(pb, "WAVE");
/* format header */
fmt = start_tag(pb, "fmt ");
if (put_wav_header(pb, &s->streams[0]->codec) < 0) {
av_free(wav);
return -1;
}
end_tag(pb, fmt);
/* data header */
wav->data = start_tag(pb, "data");
put_flush_packet(pb);
return 0;
}
static int wav_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 wav_write_trailer(AVFormatContext *s)
{
ByteIOContext *pb = &s->pb;
WAVContext *wav = s->priv_data;
offset_t file_size;
if (!url_is_streamed(&s->pb)) {
end_tag(pb, wav->data);
/* update file size */
file_size = url_ftell(pb);
url_fseek(pb, 4, SEEK_SET);
put_le32(pb, (UINT32)(file_size - 8));
url_fseek(pb, file_size, SEEK_SET);
put_flush_packet(pb);
}
return 0;
}
/* return the size of the found tag */
/* XXX: > 2GB ? */
static int find_tag(ByteIOContext *pb, UINT32 tag1)
{
unsigned int tag;
int size;
for(;;) {
if (url_feof(pb))
return -1;
tag = get_le32(pb);
size = get_le32(pb);
if (tag == tag1)
break;
url_fseek(pb, size, SEEK_CUR);
}
if (size < 0)
size = 0x7fffffff;
return size;
}
static int wav_probe(AVProbeData *p)
{
/* check file header */
if (p->buf_size <= 32)
return 0;
if (p->buf[0] == 'R' && p->buf[1] == 'I' &&
p->buf[2] == 'F' && p->buf[3] == 'F' &&
p->buf[8] == 'W' && p->buf[9] == 'A' &&
p->buf[10] == 'V' && p->buf[11] == 'E')
return AVPROBE_SCORE_MAX;
else
return 0;
}
/* wav input */
static int wav_read_header(AVFormatContext *s,
AVFormatParameters *ap)
{
int size;
unsigned int tag;
ByteIOContext *pb = &s->pb;
unsigned int id, channels, rate, bit_rate, extra_size, bps;
AVStream *st;
/* check RIFF header */
tag = get_le32(pb);
if (tag != MKTAG('R', 'I', 'F', 'F'))
return -1;
get_le32(pb); /* file size */
tag = get_le32(pb);
if (tag != MKTAG('W', 'A', 'V', 'E'))
return -1;
/* parse fmt header */
size = find_tag(pb, MKTAG('f', 'm', 't', ' '));
if (size < 0)
return -1;
id = get_le16(pb);
channels = get_le16(pb);
rate = get_le32(pb);
bit_rate = get_le32(pb) * 8;
get_le16(pb); /* block align */
bps = get_le16(pb); /* bits per sample */
if (size >= 18) {
/* wav_extra_size */
extra_size = get_le16(pb);
/* skip unused data */
url_fseek(pb, size - 18, SEEK_CUR);
}
size = find_tag(pb, MKTAG('d', 'a', 't', 'a'));
if (size < 0)
return -1;
/* now we are ready: build format streams */
st = av_new_stream(s, 0);
if (!st)
return AVERROR_NOMEM;
st->codec.codec_type = CODEC_TYPE_AUDIO;
st->codec.codec_tag = id;
st->codec.codec_id = wav_codec_get_id(id, bps);
st->codec.channels = channels;
st->codec.sample_rate = rate;
return 0;
}
#define MAX_SIZE 4096
static int wav_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 wav_read_close(AVFormatContext *s)
{
return 0;
}
static AVInputFormat wav_iformat = {
"wav",
"wav format",
0,
wav_probe,
wav_read_header,
wav_read_packet,
wav_read_close,
};
static AVOutputFormat wav_oformat = {
"wav",
"wav format",
"audio/x-wav",
"wav",
sizeof(WAVContext),
CODEC_ID_PCM_S16LE,
CODEC_ID_NONE,
wav_write_header,
wav_write_packet,
wav_write_trailer,
};
int wav_init(void)
{
av_register_input_format(&wav_iformat);
av_register_output_format(&wav_oformat);
return 0;
}
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