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FFmpeg/libavformat/kvag.c
Zane van Iperen 3cc4a140ef
avformat/kvag: allow seeking to start
Allows "ffplay -loop" to work.

Signed-off-by: Zane van Iperen <zane@zanevaniperen.com>
2021-03-25 12:51:10 +10:00

208 lines
6.0 KiB
C

/*
* Simon & Schuster Interactive VAG (de)muxer
*
* Copyright (C) 2020 Zane van Iperen (zane@zanevaniperen.com)
*
* 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
*/
#include "avformat.h"
#include "internal.h"
#include "rawenc.h"
#include "libavutil/intreadwrite.h"
#define KVAG_TAG MKTAG('K', 'V', 'A', 'G')
#define KVAG_HEADER_SIZE 14
#define KVAG_MAX_READ_SIZE 4096
typedef struct KVAGHeader {
uint32_t magic;
uint32_t data_size;
uint32_t sample_rate;
uint16_t stereo;
} KVAGHeader;
#if CONFIG_KVAG_DEMUXER
static int kvag_probe(const AVProbeData *p)
{
if (AV_RL32(p->buf) != KVAG_TAG)
return 0;
return AVPROBE_SCORE_EXTENSION + 1;
}
static int kvag_read_header(AVFormatContext *s)
{
int ret;
AVStream *st;
KVAGHeader hdr;
AVCodecParameters *par;
uint8_t buf[KVAG_HEADER_SIZE];
if (!(st = avformat_new_stream(s, NULL)))
return AVERROR(ENOMEM);
if ((ret = avio_read(s->pb, buf, KVAG_HEADER_SIZE)) < 0)
return ret;
else if (ret != KVAG_HEADER_SIZE)
return AVERROR(EIO);
hdr.magic = AV_RL32(buf + 0);
hdr.data_size = AV_RL32(buf + 4);
hdr.sample_rate = AV_RL32(buf + 8);
hdr.stereo = AV_RL16(buf + 12);
par = st->codecpar;
par->codec_type = AVMEDIA_TYPE_AUDIO;
par->codec_id = AV_CODEC_ID_ADPCM_IMA_SSI;
par->format = AV_SAMPLE_FMT_S16;
if (hdr.stereo) {
par->channel_layout = AV_CH_LAYOUT_STEREO;
par->channels = 2;
} else {
par->channel_layout = AV_CH_LAYOUT_MONO;
par->channels = 1;
}
par->sample_rate = hdr.sample_rate;
par->bits_per_coded_sample = 4;
par->bits_per_raw_sample = 16;
par->block_align = 1;
par->bit_rate = par->channels *
(uint64_t)par->sample_rate *
par->bits_per_coded_sample;
avpriv_set_pts_info(st, 64, 1, par->sample_rate);
st->start_time = 0;
st->duration = hdr.data_size *
(8 / par->bits_per_coded_sample) /
par->channels;
return 0;
}
static int kvag_read_packet(AVFormatContext *s, AVPacket *pkt)
{
int ret;
AVCodecParameters *par = s->streams[0]->codecpar;
if ((ret = av_get_packet(s->pb, pkt, KVAG_MAX_READ_SIZE)) < 0)
return ret;
pkt->flags &= ~AV_PKT_FLAG_CORRUPT;
pkt->stream_index = 0;
pkt->duration = ret * (8 / par->bits_per_coded_sample) / par->channels;
return 0;
}
static int kvag_seek(AVFormatContext *s, int stream_index,
int64_t pts, int flags)
{
if (pts != 0)
return AVERROR(EINVAL);
return avio_seek(s->pb, KVAG_HEADER_SIZE, SEEK_SET);
}
AVInputFormat ff_kvag_demuxer = {
.name = "kvag",
.long_name = NULL_IF_CONFIG_SMALL("Simon & Schuster Interactive VAG"),
.read_probe = kvag_probe,
.read_header = kvag_read_header,
.read_packet = kvag_read_packet,
.read_seek = kvag_seek,
};
#endif
#if CONFIG_KVAG_MUXER
static int kvag_write_init(AVFormatContext *s)
{
AVCodecParameters *par;
if (s->nb_streams != 1) {
av_log(s, AV_LOG_ERROR, "KVAG files have exactly one stream\n");
return AVERROR(EINVAL);
}
par = s->streams[0]->codecpar;
if (par->codec_id != AV_CODEC_ID_ADPCM_IMA_SSI) {
av_log(s, AV_LOG_ERROR, "%s codec not supported\n",
avcodec_get_name(par->codec_id));
return AVERROR(EINVAL);
}
if (par->channels > 2) {
av_log(s, AV_LOG_ERROR, "KVAG files only support up to 2 channels\n");
return AVERROR(EINVAL);
}
if (!(s->pb->seekable & AVIO_SEEKABLE_NORMAL)) {
av_log(s, AV_LOG_WARNING, "Stream not seekable, unable to write output file\n");
return AVERROR(EINVAL);
}
return 0;
}
static int kvag_write_header(AVFormatContext *s)
{
uint8_t buf[KVAG_HEADER_SIZE];
AVCodecParameters *par = s->streams[0]->codecpar;
AV_WL32(buf + 0, KVAG_TAG);
AV_WL32(buf + 4, 0); /* Data size, we fix this up later. */
AV_WL32(buf + 8, par->sample_rate);
AV_WL16(buf + 12, par->channels == 2);
avio_write(s->pb, buf, sizeof(buf));
return 0;
}
static int kvag_write_trailer(AVFormatContext *s)
{
int64_t file_size, data_size;
file_size = avio_tell(s->pb);
data_size = file_size - KVAG_HEADER_SIZE;
if (data_size < UINT32_MAX) {
avio_seek(s->pb, 4, SEEK_SET);
avio_wl32(s->pb, (uint32_t)data_size);
avio_seek(s->pb, file_size, SEEK_SET);
} else {
av_log(s, AV_LOG_WARNING,
"Filesize %"PRId64" invalid for KVAG, output file will be broken\n",
file_size);
}
return 0;
}
AVOutputFormat ff_kvag_muxer = {
.name = "kvag",
.long_name = NULL_IF_CONFIG_SMALL("Simon & Schuster Interactive VAG"),
.extensions = "vag",
.audio_codec = AV_CODEC_ID_ADPCM_IMA_SSI,
.video_codec = AV_CODEC_ID_NONE,
.init = kvag_write_init,
.write_header = kvag_write_header,
.write_packet = ff_raw_write_packet,
.write_trailer = kvag_write_trailer
};
#endif