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  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.  
  30. typedef struct RedSparkContext {
  31.     int         samples_count;
  32. } RedSparkContext;
  33.  
  34. static int redspark_probe(AVProbeData *p)
  35. {
  36.     uint32_t key, data;
  37.     uint8_t header[8];
  38.  
  39.     /* Decrypt first 8 bytes of the header */
  40.     data = AV_RB32(p->buf);
  41.     data = data ^ (key = data ^ 0x52656453);
  42.     AV_WB32(header, data);
  43.     key = (key << 11) | (key >> 21);
  44.  
  45.     data = AV_RB32(p->buf + 4) ^ (((key << 3) | (key >> 29)) + key);
  46.     AV_WB32(header + 4, data);
  47.  
  48.     if (AV_RB64(header) == AV_RB64("RedSpark"))
  49.         return AVPROBE_SCORE_MAX;
  50.  
  51.     return 0;
  52. }
  53.  
  54. static int redspark_read_header(AVFormatContext *s)
  55. {
  56.     AVIOContext *pb = s->pb;
  57.     RedSparkContext *redspark = s->priv_data;
  58.     AVCodecContext *codec;
  59.     GetByteContext gbc;
  60.     int i, coef_off, ret = 0;
  61.     uint32_t key, data;
  62.     uint8_t *header, *pbc;
  63.     AVStream *st;
  64.  
  65.     st = avformat_new_stream(s, NULL);
  66.     if (!st)
  67.         return AVERROR(ENOMEM);
  68.     codec = st->codec;
  69.  
  70.     header = av_malloc(HEADER_SIZE + FF_INPUT_BUFFER_PADDING_SIZE);
  71.     if (!header)
  72.         return AVERROR(ENOMEM);
  73.     pbc = header;
  74.  
  75.     /* Decrypt header */
  76.     data = avio_rb32(pb);
  77.     data = data ^ (key = data ^ 0x52656453);
  78.     bytestream_put_be32(&pbc, data);
  79.     key = (key << 11) | (key >> 21);
  80.  
  81.     for (i = 4; i < HEADER_SIZE; i += 4) {
  82.         data = avio_rb32(pb) ^ (key = ((key << 3) | (key >> 29)) + key);
  83.         bytestream_put_be32(&pbc, data);
  84.     }
  85.  
  86.     codec->codec_id    = AV_CODEC_ID_ADPCM_THP;
  87.     codec->codec_type  = AVMEDIA_TYPE_AUDIO;
  88.  
  89.     bytestream2_init(&gbc, header, HEADER_SIZE);
  90.     bytestream2_seek(&gbc, 0x3c, SEEK_SET);
  91.     codec->sample_rate = bytestream2_get_be32u(&gbc);
  92.     if (codec->sample_rate <= 0 || codec->sample_rate > 96000) {
  93.         av_log(s, AV_LOG_ERROR, "Invalid sample rate: %d\n", codec->sample_rate);
  94.         ret = AVERROR_INVALIDDATA;
  95.         goto fail;
  96.     }
  97.  
  98.     st->duration = bytestream2_get_be32u(&gbc) * 14;
  99.     redspark->samples_count = 0;
  100.     bytestream2_skipu(&gbc, 10);
  101.     codec->channels = bytestream2_get_byteu(&gbc);
  102.     if (!codec->channels) {
  103.         ret = AVERROR_INVALIDDATA;
  104.         goto fail;
  105.     }
  106.  
  107.     coef_off = 0x54 + codec->channels * 8;
  108.     if (bytestream2_get_byteu(&gbc)) // Loop flag
  109.         coef_off += 16;
  110.  
  111.     if (coef_off + codec->channels * (32 + 14) > HEADER_SIZE) {
  112.         ret = AVERROR_INVALIDDATA;
  113.         goto fail;
  114.     }
  115.  
  116.     if (ff_alloc_extradata(codec, 32 * codec->channels)) {
  117.         ret = AVERROR(ENOMEM);
  118.         goto fail;
  119.     }
  120.  
  121.     /* Get the ADPCM table */
  122.     bytestream2_seek(&gbc, coef_off, SEEK_SET);
  123.     for (i = 0; i < codec->channels; i++) {
  124.         if (bytestream2_get_bufferu(&gbc, codec->extradata + i * 32, 32) != 32) {
  125.             ret = AVERROR_INVALIDDATA;
  126.             goto fail;
  127.         }
  128.         bytestream2_skipu(&gbc, 14);
  129.     }
  130.  
  131.     avpriv_set_pts_info(st, 64, 1, codec->sample_rate);
  132.  
  133. fail:
  134.     av_free(header);
  135.  
  136.     return ret;
  137. }
  138.  
  139. static int redspark_read_packet(AVFormatContext *s, AVPacket *pkt)
  140. {
  141.     AVCodecContext *codec = s->streams[0]->codec;
  142.     RedSparkContext *redspark = s->priv_data;
  143.     uint32_t size = 8 * codec->channels;
  144.     int ret;
  145.  
  146.     if (url_feof(s->pb) || redspark->samples_count == s->streams[0]->duration)
  147.         return AVERROR_EOF;
  148.  
  149.     ret = av_get_packet(s->pb, pkt, size);
  150.     if (ret != size) {
  151.         av_free_packet(pkt);
  152.         return AVERROR(EIO);
  153.     }
  154.  
  155.     pkt->duration = 14;
  156.     redspark->samples_count += pkt->duration;
  157.     pkt->stream_index = 0;
  158.  
  159.     return ret;
  160. }
  161.  
  162. AVInputFormat ff_redspark_demuxer = {
  163.     .name           =   "redspark",
  164.     .long_name      =   NULL_IF_CONFIG_SMALL("RedSpark"),
  165.     .priv_data_size =   sizeof(RedSparkContext),
  166.     .read_probe     =   redspark_probe,
  167.     .read_header    =   redspark_read_header,
  168.     .read_packet    =   redspark_read_packet,
  169.     .extensions     =   "rsd",
  170. };
  171.