FFmpeg/libavformat/adxdec.c
Paul B Mahol e0d0565425 avformat/adxdec: demux multiple blocks at once
Improves decoding speed by 24x
2020-10-03 21:49:39 +02:00

143 lines
4.0 KiB
C

/*
* Copyright (c) 2011 Justin Ruggles
*
* 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
* CRI ADX demuxer
*/
#include "libavutil/intreadwrite.h"
#include "avformat.h"
#include "internal.h"
#define BLOCK_SIZE 18
#define BLOCK_SAMPLES 32
typedef struct ADXDemuxerContext {
int header_size;
} ADXDemuxerContext;
static int adx_probe(const AVProbeData *p)
{
int offset;
if (AV_RB16(p->buf) != 0x8000)
return 0;
offset = AV_RB16(&p->buf[2]);
if ( offset < 8
|| offset > p->buf_size - 4
|| memcmp(p->buf + offset - 2, "(c)CRI", 6))
return 0;
return AVPROBE_SCORE_MAX * 3 / 4;
}
static int adx_read_packet(AVFormatContext *s, AVPacket *pkt)
{
ADXDemuxerContext *c = s->priv_data;
AVCodecParameters *par = s->streams[0]->codecpar;
int ret, size;
if (avio_feof(s->pb))
return AVERROR_EOF;
if (par->channels <= 0) {
av_log(s, AV_LOG_ERROR, "invalid number of channels %d\n", par->channels);
return AVERROR_INVALIDDATA;
}
size = BLOCK_SIZE * par->channels;
pkt->pos = avio_tell(s->pb);
pkt->stream_index = 0;
ret = av_get_packet(s->pb, pkt, size * 128);
if (ret < 0)
return ret;
if ((ret % size) && ret >= size) {
size = ret - (ret % size);
av_shrink_packet(pkt, size);
pkt->flags &= ~AV_PKT_FLAG_CORRUPT;
} else if (ret < size) {
return AVERROR(EIO);
} else {
size = ret;
}
pkt->duration = size / (BLOCK_SIZE * par->channels);
pkt->pts = (pkt->pos - c->header_size) / (BLOCK_SIZE * par->channels);
return 0;
}
static int adx_read_header(AVFormatContext *s)
{
ADXDemuxerContext *c = s->priv_data;
AVCodecParameters *par;
int ret;
AVStream *st = avformat_new_stream(s, NULL);
if (!st)
return AVERROR(ENOMEM);
par = s->streams[0]->codecpar;
if (avio_rb16(s->pb) != 0x8000)
return AVERROR_INVALIDDATA;
c->header_size = avio_rb16(s->pb) + 4;
avio_seek(s->pb, -4, SEEK_CUR);
if ((ret = ff_get_extradata(s, par, s->pb, c->header_size)) < 0)
return ret;
if (par->extradata_size < 12) {
av_log(s, AV_LOG_ERROR, "Invalid extradata size.\n");
return AVERROR_INVALIDDATA;
}
par->channels = AV_RB8 (par->extradata + 7);
par->sample_rate = AV_RB32(par->extradata + 8);
if (par->channels <= 0) {
av_log(s, AV_LOG_ERROR, "invalid number of channels %d\n", par->channels);
return AVERROR_INVALIDDATA;
}
if (par->sample_rate <= 0) {
av_log(s, AV_LOG_ERROR, "Invalid sample rate %d\n", par->sample_rate);
return AVERROR_INVALIDDATA;
}
par->codec_type = AVMEDIA_TYPE_AUDIO;
par->codec_id = s->iformat->raw_codec_id;
par->bit_rate = (int64_t)par->sample_rate * par->channels * BLOCK_SIZE * 8LL / BLOCK_SAMPLES;
avpriv_set_pts_info(st, 64, BLOCK_SAMPLES, par->sample_rate);
return 0;
}
AVInputFormat ff_adx_demuxer = {
.name = "adx",
.long_name = NULL_IF_CONFIG_SMALL("CRI ADX"),
.read_probe = adx_probe,
.priv_data_size = sizeof(ADXDemuxerContext),
.read_header = adx_read_header,
.read_packet = adx_read_packet,
.extensions = "adx",
.raw_codec_id = AV_CODEC_ID_ADPCM_ADX,
.flags = AVFMT_GENERIC_INDEX,
};