ffmpeg/libavformat/redspark.c

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/*
* RedSpark demuxer
* Copyright (c) 2013 James Almer
*
* 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 "libavcodec/bytestream.h"
#include "libavutil/intreadwrite.h"
#include "avformat.h"
#include "avio.h"
#include "internal.h"
#define HEADER_SIZE 4096
typedef struct RedSparkContext {
int samples_count;
} RedSparkContext;
static int redspark_probe(AVProbeData *p)
{
uint32_t key, data;
uint8_t header[8];
/* Decrypt first 8 bytes of the header */
data = AV_RB32(p->buf);
data = data ^ (key = data ^ 0x52656453);
AV_WB32(header, data);
key = (key << 11) | (key >> 21);
data = AV_RB32(p->buf + 4) ^ (((key << 3) | (key >> 29)) + key);
AV_WB32(header + 4, data);
if (AV_RB64(header) == AV_RB64("RedSpark"))
return AVPROBE_SCORE_MAX;
return 0;
}
static int redspark_read_header(AVFormatContext *s)
{
AVIOContext *pb = s->pb;
RedSparkContext *redspark = s->priv_data;
AVCodecContext *codec;
GetByteContext gbc;
int i, coef_off, ret = 0;
uint32_t key, data;
uint8_t *header, *pbc;
AVStream *st;
st = avformat_new_stream(s, NULL);
if (!st)
return AVERROR(ENOMEM);
codec = st->codec;
header = av_malloc(HEADER_SIZE + FF_INPUT_BUFFER_PADDING_SIZE);
if (!header)
return AVERROR(ENOMEM);
pbc = header;
/* Decrypt header */
data = avio_rb32(pb);
data = data ^ (key = data ^ 0x52656453);
bytestream_put_be32(&pbc, data);
key = (key << 11) | (key >> 21);
for (i = 4; i < HEADER_SIZE; i += 4) {
data = avio_rb32(pb) ^ (key = ((key << 3) | (key >> 29)) + key);
bytestream_put_be32(&pbc, data);
}
codec->codec_id = AV_CODEC_ID_ADPCM_THP;
codec->codec_type = AVMEDIA_TYPE_AUDIO;
bytestream2_init(&gbc, header, HEADER_SIZE);
bytestream2_seek(&gbc, 0x3c, SEEK_SET);
codec->sample_rate = bytestream2_get_be32u(&gbc);
if (codec->sample_rate <= 0 || codec->sample_rate > 96000) {
av_log(s, AV_LOG_ERROR, "Invalid sample rate: %d\n", codec->sample_rate);
ret = AVERROR_INVALIDDATA;
goto fail;
}
st->duration = bytestream2_get_be32u(&gbc) * 14;
redspark->samples_count = 0;
bytestream2_skipu(&gbc, 10);
codec->channels = bytestream2_get_byteu(&gbc);
if (!codec->channels) {
ret = AVERROR_INVALIDDATA;
goto fail;
}
coef_off = 0x54 + codec->channels * 8;
if (bytestream2_get_byteu(&gbc)) // Loop flag
coef_off += 16;
if (coef_off + codec->channels * (32 + 14) > HEADER_SIZE) {
ret = AVERROR_INVALIDDATA;
goto fail;
}
if (ff_alloc_extradata(codec, 32 * codec->channels)) {
ret = AVERROR(ENOMEM);
goto fail;
}
/* Get the ADPCM table */
bytestream2_seek(&gbc, coef_off, SEEK_SET);
for (i = 0; i < codec->channels; i++) {
if (bytestream2_get_bufferu(&gbc, codec->extradata + i * 32, 32) != 32) {
ret = AVERROR_INVALIDDATA;
goto fail;
}
bytestream2_skipu(&gbc, 14);
}
avpriv_set_pts_info(st, 64, 1, codec->sample_rate);
fail:
av_free(header);
return ret;
}
static int redspark_read_packet(AVFormatContext *s, AVPacket *pkt)
{
AVCodecContext *codec = s->streams[0]->codec;
RedSparkContext *redspark = s->priv_data;
uint32_t size = 8 * codec->channels;
int ret;
if (url_feof(s->pb) || redspark->samples_count == s->streams[0]->duration)
return AVERROR_EOF;
ret = av_get_packet(s->pb, pkt, size);
if (ret != size) {
av_free_packet(pkt);
return AVERROR(EIO);
}
pkt->duration = 14;
redspark->samples_count += pkt->duration;
pkt->stream_index = 0;
return ret;
}
AVInputFormat ff_redspark_demuxer = {
.name = "redspark",
.long_name = NULL_IF_CONFIG_SMALL("RedSpark"),
.priv_data_size = sizeof(RedSparkContext),
.read_probe = redspark_probe,
.read_header = redspark_read_header,
.read_packet = redspark_read_packet,
.extensions = "rsd",
};