iss.c 3.9 KB

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  1. /*
  2. * ISS (.iss) file demuxer
  3. * Copyright (c) 2008 Jaikrishnan Menon <realityman@gmx.net>
  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. * @file
  23. * Funcom ISS file demuxer
  24. * @author Jaikrishnan Menon
  25. * @see http://wiki.multimedia.cx/index.php?title=FunCom_ISS
  26. */
  27. #include "avformat.h"
  28. #include "libavutil/avstring.h"
  29. #define ISS_SIG "IMA_ADPCM_Sound"
  30. #define ISS_SIG_LEN 15
  31. #define MAX_TOKEN_SIZE 20
  32. typedef struct {
  33. int packet_size;
  34. int sample_start_pos;
  35. } IssDemuxContext;
  36. static void get_token(AVIOContext *s, char *buf, int maxlen)
  37. {
  38. int i = 0;
  39. char c;
  40. while ((c = avio_r8(s))) {
  41. if(c == ' ')
  42. break;
  43. if (i < maxlen-1)
  44. buf[i++] = c;
  45. }
  46. if(!c)
  47. avio_r8(s);
  48. buf[i] = 0; /* Ensure null terminated, but may be truncated */
  49. }
  50. static int iss_probe(AVProbeData *p)
  51. {
  52. if (strncmp(p->buf, ISS_SIG, ISS_SIG_LEN))
  53. return 0;
  54. return AVPROBE_SCORE_MAX;
  55. }
  56. static av_cold int iss_read_header(AVFormatContext *s, AVFormatParameters *ap)
  57. {
  58. IssDemuxContext *iss = s->priv_data;
  59. AVIOContext *pb = s->pb;
  60. AVStream *st;
  61. char token[MAX_TOKEN_SIZE];
  62. int stereo, rate_divisor;
  63. get_token(pb, token, sizeof(token)); //"IMA_ADPCM_Sound"
  64. get_token(pb, token, sizeof(token)); //packet size
  65. sscanf(token, "%d", &iss->packet_size);
  66. get_token(pb, token, sizeof(token)); //File ID
  67. get_token(pb, token, sizeof(token)); //out size
  68. get_token(pb, token, sizeof(token)); //stereo
  69. sscanf(token, "%d", &stereo);
  70. get_token(pb, token, sizeof(token)); //Unknown1
  71. get_token(pb, token, sizeof(token)); //RateDivisor
  72. sscanf(token, "%d", &rate_divisor);
  73. get_token(pb, token, sizeof(token)); //Unknown2
  74. get_token(pb, token, sizeof(token)); //Version ID
  75. get_token(pb, token, sizeof(token)); //Size
  76. iss->sample_start_pos = avio_tell(pb);
  77. st = av_new_stream(s, 0);
  78. if (!st)
  79. return AVERROR(ENOMEM);
  80. st->codec->codec_type = AVMEDIA_TYPE_AUDIO;
  81. st->codec->codec_id = CODEC_ID_ADPCM_IMA_ISS;
  82. st->codec->channels = stereo ? 2 : 1;
  83. st->codec->sample_rate = 44100;
  84. if(rate_divisor > 0)
  85. st->codec->sample_rate /= rate_divisor;
  86. st->codec->bits_per_coded_sample = 4;
  87. st->codec->bit_rate = st->codec->channels * st->codec->sample_rate
  88. * st->codec->bits_per_coded_sample;
  89. st->codec->block_align = iss->packet_size;
  90. av_set_pts_info(st, 32, 1, st->codec->sample_rate);
  91. return 0;
  92. }
  93. static int iss_read_packet(AVFormatContext *s, AVPacket *pkt)
  94. {
  95. IssDemuxContext *iss = s->priv_data;
  96. int ret = av_get_packet(s->pb, pkt, iss->packet_size);
  97. if(ret != iss->packet_size)
  98. return AVERROR(EIO);
  99. pkt->stream_index = 0;
  100. pkt->pts = avio_tell(s->pb) - iss->sample_start_pos;
  101. if(s->streams[0]->codec->channels > 0)
  102. pkt->pts /= s->streams[0]->codec->channels*2;
  103. return 0;
  104. }
  105. AVInputFormat ff_iss_demuxer = {
  106. .name = "ISS",
  107. .long_name = NULL_IF_CONFIG_SMALL("Funcom ISS format"),
  108. .priv_data_size = sizeof(IssDemuxContext),
  109. .read_probe = iss_probe,
  110. .read_header = iss_read_header,
  111. .read_packet = iss_read_packet,
  112. };