FFmpeg/libavformat/xa.c
Andreas Rheinhardt b800327f4c avformat/avformat: Add FFInputFormat, hide internals of AVInputFormat
This commit does for AVInputFormat what commit
59c9dc82f4 did for AVOutputFormat:
It adds a new type FFInputFormat, moves all the internals
of AVInputFormat to it and adds a now reduced AVInputFormat
as first member.

This does not affect/improve extensibility of both public
or private fields for demuxers (it is still a mess due to lavd).

This is possible since 50f34172e0
(which removed the last usage of an internal field of AVInputFormat
in fftools).

(Hint: tools/probetest.c accesses the internals of FFInputFormat
as well, but given that it is a testing tool this is not considered
a problem.)

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
2024-03-07 08:53:31 -03:00

133 lines
3.9 KiB
C

/*
* Maxis XA (.xa) File Demuxer
* Copyright (c) 2008 Robert Marston
*
* This file is part of FFmpeg.
*
* FFmpeg 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 2.1 of the License, or (at your option) any later version.
*
* FFmpeg 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 FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
/**
* @file
* Maxis XA File Demuxer
* by Robert Marston (rmarston@gmail.com)
* for more information on the XA audio format see
* http://wiki.multimedia.cx/index.php?title=Maxis_XA
*/
#include "libavutil/intreadwrite.h"
#include "avformat.h"
#include "demux.h"
#include "internal.h"
#define XA00_TAG MKTAG('X', 'A', 0, 0)
#define XAI0_TAG MKTAG('X', 'A', 'I', 0)
#define XAJ0_TAG MKTAG('X', 'A', 'J', 0)
typedef struct MaxisXADemuxContext {
uint32_t out_size;
uint32_t sent_bytes;
} MaxisXADemuxContext;
static int xa_probe(const AVProbeData *p)
{
int channels, srate, bits_per_sample;
if (p->buf_size < 24)
return 0;
switch(AV_RL32(p->buf)) {
case XA00_TAG:
case XAI0_TAG:
case XAJ0_TAG:
break;
default:
return 0;
}
channels = AV_RL16(p->buf + 10);
srate = AV_RL32(p->buf + 12);
bits_per_sample = AV_RL16(p->buf + 22);
if (!channels || channels > 8 || !srate || srate > 192000 ||
bits_per_sample < 4 || bits_per_sample > 32)
return 0;
return AVPROBE_SCORE_EXTENSION;
}
static int xa_read_header(AVFormatContext *s)
{
MaxisXADemuxContext *xa = s->priv_data;
AVIOContext *pb = s->pb;
AVStream *st;
/*Set up the XA Audio Decoder*/
st = avformat_new_stream(s, NULL);
if (!st)
return AVERROR(ENOMEM);
st->codecpar->codec_type = AVMEDIA_TYPE_AUDIO;
st->codecpar->codec_id = AV_CODEC_ID_ADPCM_EA_MAXIS_XA;
avio_skip(pb, 4); /* Skip the XA ID */
xa->out_size = avio_rl32(pb);
avio_skip(pb, 2); /* Skip the tag */
st->codecpar->ch_layout.nb_channels = avio_rl16(pb);
st->codecpar->sample_rate = avio_rl32(pb);
avio_skip(pb, 4); /* Skip average byte rate */
avio_skip(pb, 2); /* Skip block align */
avio_skip(pb, 2); /* Skip bits-per-sample */
if (!st->codecpar->ch_layout.nb_channels || !st->codecpar->sample_rate)
return AVERROR_INVALIDDATA;
st->codecpar->bit_rate = av_clip(15LL * st->codecpar->ch_layout.nb_channels * 8 *
st->codecpar->sample_rate / 28, 0, INT_MAX);
avpriv_set_pts_info(st, 64, 1, st->codecpar->sample_rate);
st->start_time = 0;
return 0;
}
static int xa_read_packet(AVFormatContext *s,
AVPacket *pkt)
{
MaxisXADemuxContext *xa = s->priv_data;
AVStream *st = s->streams[0];
AVIOContext *pb = s->pb;
unsigned int packet_size;
int ret;
if (xa->sent_bytes >= xa->out_size)
return AVERROR_EOF;
/* 1 byte header and 14 bytes worth of samples * number channels per block */
packet_size = 15*st->codecpar->ch_layout.nb_channels;
ret = av_get_packet(pb, pkt, packet_size);
if(ret < 0)
return ret;
pkt->stream_index = st->index;
xa->sent_bytes += packet_size;
pkt->duration = 28;
return ret;
}
const FFInputFormat ff_xa_demuxer = {
.p.name = "xa",
.p.long_name = NULL_IF_CONFIG_SMALL("Maxis XA"),
.priv_data_size = sizeof(MaxisXADemuxContext),
.read_probe = xa_probe,
.read_header = xa_read_header,
.read_packet = xa_read_packet,
};