libavformat/redspark.c

   1 /*
   2  * RedSpark demuxer
   3  * Copyright (c) 2013 James Almer
   4  *
   5  * This file is part of FFmpeg.
   6  *
   7  * FFmpeg is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU Lesser General Public
   9  * License as published by the Free Software Foundation; either
  10  * version 2.1 of the License, or (at your option) any later version.
  11  *
  12  * FFmpeg is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  * Lesser General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU Lesser General Public
  18  * License along with FFmpeg; if not, write to the Free Software
  19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  20  */
  21
  22 #include "libavcodec/bytestream.h"
  23 #include "libavutil/intreadwrite.h"
  24 #include "avformat.h"
  25 #include "avio.h"
  26 #include "internal.h"
  27
  28 #define HEADER_SIZE 4096
  29 #define rol(value, bits) (((value) << (bits)) | ((value) >> (32 - (bits))))
  30
  31 typedef struct RedSparkContext {
  32     int         samples_count;
  33 } RedSparkContext;
  34
  35 static int redspark_probe(AVProbeData *p)
  36 {
  37     uint32_t key, data;
  38     uint8_t header[8];
  39
  40     /* Decrypt first 8 bytes of the header */
  41     data = AV_RB32(p->buf);
  42     key  = data ^ 0x52656453;
  43     data ^= key;
  44     AV_WB32(header, data);
  45     key = rol(key, 11);
  46
  47     key += rol(key, 3);
  48     data = AV_RB32(p->buf + 4) ^ key;
  49     AV_WB32(header + 4, data);
  50
  51     if (AV_RB64(header) == AV_RB64("RedSpark"))
  52         return AVPROBE_SCORE_MAX;
  53
  54     return 0;
  55 }
  56
  57 static int redspark_read_header(AVFormatContext *s)
  58 {
  59     AVIOContext *pb = s->pb;
  60     RedSparkContext *redspark = s->priv_data;
  61     AVCodecParameters *par;
  62     GetByteContext gbc;
  63     int i, coef_off, ret = 0;
  64     uint32_t key, data;
  65     uint8_t header[HEADER_SIZE];
  66     AVStream *st;
  67
  68     st = avformat_new_stream(s, NULL);
  69     if (!st)
  70         return AVERROR(ENOMEM);
  71     par = st->codecpar;
  72
  73     /* Decrypt header */
  74     data = avio_rb32(pb);
  75     key  = data ^ 0x52656453;
  76     data ^= key;
  77     AV_WB32(header, data);
  78     key = rol(key, 11);
  79
  80     for (i = 4; i < HEADER_SIZE; i += 4) {
  81         key += rol(key, 3);
  82         data = avio_rb32(pb) ^ key;
  83         AV_WB32(header + i, data);
  84     }
  85
  86     par->codec_id    = AV_CODEC_ID_ADPCM_THP;
  87     par->codec_type  = AVMEDIA_TYPE_AUDIO;
  88
  89     bytestream2_init(&gbc, header, HEADER_SIZE);
  90     bytestream2_seek(&gbc, 0x3c, SEEK_SET);
  91     par->sample_rate = bytestream2_get_be32u(&gbc);
  92     if (par->sample_rate <= 0 || par->sample_rate > 96000) {
  93         av_log(s, AV_LOG_ERROR, "Invalid sample rate: %d\n", par->sample_rate);
  94         return AVERROR_INVALIDDATA;
  95     }
  96
  97     st->duration = bytestream2_get_be32u(&gbc) * 14;
  98     redspark->samples_count = 0;
  99     bytestream2_skipu(&gbc, 10);
 100     par->channels = bytestream2_get_byteu(&gbc);
 101     if (!par->channels) {
 102         return AVERROR_INVALIDDATA;
 103     }
 104
 105     coef_off = 0x54 + par->channels * 8;
 106     if (bytestream2_get_byteu(&gbc)) // Loop flag
 107         coef_off += 16;
 108
 109     if (coef_off + par->channels * (32 + 14) > HEADER_SIZE) {
 110         return AVERROR_INVALIDDATA;
 111     }
 112
 113     if (ff_alloc_extradata(par, 32 * par->channels)) {
 114         return AVERROR_INVALIDDATA;
 115     }
 116
 117     /* Get the ADPCM table */
 118     bytestream2_seek(&gbc, coef_off, SEEK_SET);
 119     for (i = 0; i < par->channels; i++) {
 120         if (bytestream2_get_bufferu(&gbc, par->extradata + i * 32, 32) != 32) {
 121             return AVERROR_INVALIDDATA;
 122         }
 123         bytestream2_skipu(&gbc, 14);
 124     }
 125
 126     avpriv_set_pts_info(st, 64, 1, par->sample_rate);
 127
 128     return ret;
 129 }
 130
 131 static int redspark_read_packet(AVFormatContext *s, AVPacket *pkt)
 132 {
 133     AVCodecParameters *par = s->streams[0]->codecpar;
 134     RedSparkContext *redspark = s->priv_data;
 135     uint32_t size = 8 * par->channels;
 136     int ret;
 137
 138     if (avio_feof(s->pb) || redspark->samples_count == s->streams[0]->duration)
 139         return AVERROR_EOF;
 140
 141     ret = av_get_packet(s->pb, pkt, size);
 142     if (ret != size) {
 143         av_packet_unref(pkt);
 144         return AVERROR(EIO);
 145     }
 146
 147     pkt->duration = 14;
 148     redspark->samples_count += pkt->duration;
 149     pkt->stream_index = 0;
 150
 151     return ret;
 152 }
 153
 154 AVInputFormat ff_redspark_demuxer = {
 155     .name           =   "redspark",
 156     .long_name      =   NULL_IF_CONFIG_SMALL("RedSpark"),
 157     .priv_data_size =   sizeof(RedSparkContext),
 158     .read_probe     =   redspark_probe,
 159     .read_header    =   redspark_read_header,
 160     .read_packet    =   redspark_read_packet,
 161     .extensions     =   "rsd",
 162 };