FFmpeg: libavformat/iss.c Source File

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libavformat

iss.c

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1 /*

2 * ISS (.iss) file demuxer

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 */

22 /**

23 * @file

24 * Funcom ISS file demuxer

25 * @author Jaikrishnan Menon

26 * @see http://wiki.multimedia.cx/index.php?title=FunCom_ISS

27 */

29 #include "libavutil/channel_layout.h"

30 #include "avformat.h"

31 #include "internal.h"

32 #include "libavutil/avstring.h"

34 #define ISS_SIG "IMA_ADPCM_Sound"

35 #define ISS_SIG_LEN 15

36 #define MAX_TOKEN_SIZE 20

38 typedef struct IssDemuxContext {

39 int packet_size;

40 int sample_start_pos;

41 } IssDemuxContext;

43 static void get_token(AVIOContext *s, char *buf, int maxlen)

44 {

45 int i = 0;

46 char c;

48 while ((c = avio_r8(s))) {

49 if(c == ' ')

50 break;

51 if (i < maxlen-1)

52 buf[i++] = c;

53 }

55 if(!c)

56 avio_r8(s);

58 buf[i] = 0; /* Ensure null terminated, but may be truncated */

59 }

61 static int iss_probe(AVProbeData *p)

62 {

63 if (strncmp(p->buf, ISS_SIG, ISS_SIG_LEN))

64 return 0;

66 return AVPROBE_SCORE_MAX;

67 }

69 static av_cold int iss_read_header(AVFormatContext *s)

70 {

71 IssDemuxContext *iss = s->priv_data;

72 AVIOContext *pb = s->pb;

73 AVStream *st;

74 char token[MAX_TOKEN_SIZE];

75 int stereo, rate_divisor;

77 get_token(pb, token, sizeof(token)); //"IMA_ADPCM_Sound"

78 get_token(pb, token, sizeof(token)); //packet size

79 if (sscanf(token, "%d", &iss->packet_size) != 1) {

80 av_log(s, AV_LOG_ERROR, "Failed parsing packet size\n");

81 return AVERROR_INVALIDDATA;

82 }

83 get_token(pb, token, sizeof(token)); //File ID

84 get_token(pb, token, sizeof(token)); //out size

85 get_token(pb, token, sizeof(token)); //stereo

86 if (sscanf(token, "%d", &stereo) != 1) {

87 av_log(s, AV_LOG_ERROR, "Failed parsing stereo flag\n");

88 return AVERROR_INVALIDDATA;

89 }

90 get_token(pb, token, sizeof(token)); //Unknown1

91 get_token(pb, token, sizeof(token)); //RateDivisor

92 if (sscanf(token, "%d", &rate_divisor) != 1) {

93 av_log(s, AV_LOG_ERROR, "Failed parsing rate_divisor\n");

94 return AVERROR_INVALIDDATA;

95 }

96 get_token(pb, token, sizeof(token)); //Unknown2

97 get_token(pb, token, sizeof(token)); //Version ID

98 get_token(pb, token, sizeof(token)); //Size

100 if (iss->packet_size <= 0) {

101 av_log(s, AV_LOG_ERROR, "packet_size %d is invalid\n", iss->packet_size);

102 return AVERROR_INVALIDDATA;

103 }

104

105 iss->sample_start_pos = avio_tell(pb);

106

107 st = avformat_new_stream(s, NULL);

108 if (!st)

109 return AVERROR(ENOMEM);

110 st->codec->codec_type = AVMEDIA_TYPE_AUDIO;

111 st->codec->codec_id = AV_CODEC_ID_ADPCM_IMA_ISS;

112 if (stereo) {

113 st->codec->channels = 2;

114 st->codec->channel_layout = AV_CH_LAYOUT_STEREO;

115 } else {

116 st->codec->channels = 1;

117 st->codec->channel_layout = AV_CH_LAYOUT_MONO;

118 }

119 st->codec->sample_rate = 44100;

120 if(rate_divisor > 0)

121 st->codec->sample_rate /= rate_divisor;

122 st->codec->bits_per_coded_sample = 4;

123 st->codec->bit_rate = st->codec->channels * st->codec->sample_rate

124 * st->codec->bits_per_coded_sample;

125 st->codec->block_align = iss->packet_size;

126 avpriv_set_pts_info(st, 32, 1, st->codec->sample_rate);

127

128 return 0;

129 }

130

131 static int iss_read_packet(AVFormatContext *s, AVPacket *pkt)

132 {

133 IssDemuxContext *iss = s->priv_data;

134 int ret = av_get_packet(s->pb, pkt, iss->packet_size);

135

136 if(ret != iss->packet_size)

137 return AVERROR(EIO);

138

139 pkt->stream_index = 0;

140 pkt->pts = avio_tell(s->pb) - iss->sample_start_pos;

141 if(s->streams[0]->codec->channels > 0)

142 pkt->pts /= s->streams[0]->codec->channels*2;

143 return 0;

144 }

145

146 AVInputFormat ff_iss_demuxer = {

147 .name = "iss",

148 .long_name = NULL_IF_CONFIG_SMALL("Funcom ISS"),

149 .priv_data_size = sizeof(IssDemuxContext),

150 .read_probe = iss_probe,

151 .read_header = iss_read_header,

152 .read_packet = iss_read_packet,

153 };

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