FFmpeg: libavformat/libgme.c Source File

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libavformat

libgme.c

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1 /*

2 * This file is part of FFmpeg.

3 *

4 * FFmpeg is free software; you can redistribute it and/or

5 * modify it under the terms of the GNU Lesser General Public

6 * License as published by the Free Software Foundation; either

7 * version 2.1 of the License, or (at your option) any later version.

8 *

9 * FFmpeg is distributed in the hope that it will be useful,

10 * but WITHOUT ANY WARRANTY; without even the implied warranty of

11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU

12 * Lesser General Public License for more details.

13 *

14 * You should have received a copy of the GNU Lesser General Public

15 * License along with FFmpeg; if not, write to the Free Software

16 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

17 */

19 /**

20 * @file

21 * libgme demuxer

22 */

24 #include <gme/gme.h>

25 #include "libavutil/avstring.h"

26 #include "libavutil/eval.h"

27 #include "libavutil/opt.h"

28 #include "avformat.h"

29 #include "internal.h"

31 typedef struct GMEContext {

32 const AVClass *class;

33 Music_Emu *music_emu;

34 gme_info_t *info; ///< selected track

36 /* options */

37 int track_index;

38 int sample_rate;

39 int64_t max_size;

40 } GMEContext;

42 #define OFFSET(x) offsetof(GMEContext, x)

43 #define A AV_OPT_FLAG_AUDIO_PARAM

44 #define D AV_OPT_FLAG_DECODING_PARAM

45 static const AVOption options[] = {

46 {"track_index", "set track that should be played", OFFSET(track_index), AV_OPT_TYPE_INT, {.i64 = 0}, 0, INT_MAX, A|D},

47 {"sample_rate", "set sample rate", OFFSET(sample_rate), AV_OPT_TYPE_INT, {.i64 = 44100}, 1000, 999999, A|D},

48 {"max_size", "set max file size supported (in bytes)", OFFSET(max_size), AV_OPT_TYPE_INT64, {.i64 = 50 * 1024 * 1024}, 0, SIZE_MAX, A|D},

49 {NULL}

50 };

52 static void add_meta(AVFormatContext *s, const char *name, const char *value)

53 {

54 if (value && value[0])

55 av_dict_set(&s->metadata, name, value, 0);

56 }

58 static int load_metadata(AVFormatContext *s)

59 {

60 GMEContext *gme = s->priv_data;

61 gme_info_t *info = gme->info;

62 char buf[30];

64 add_meta(s, "system", info->system);

65 add_meta(s, "game", info->game);

66 add_meta(s, "song", info->song);

67 add_meta(s, "author", info->author);

68 add_meta(s, "copyright", info->copyright);

69 add_meta(s, "comment", info->comment);

70 add_meta(s, "dumper", info->dumper);

72 snprintf(buf, sizeof(buf), "%d", (int)gme_track_count(gme->music_emu));

73 add_meta(s, "tracks", buf);

75 return 0;

76 }

78 #define AUDIO_PKT_SIZE 512

80 static int read_header_gme(AVFormatContext *s)

81 {

82 AVStream *st;

83 AVIOContext *pb = s->pb;

84 GMEContext *gme = s->priv_data;

85 int64_t sz = avio_size(pb);

86 char *buf;

87 char dummy;

89 if (sz < 0) {

90 av_log(s, AV_LOG_WARNING, "Could not determine file size\n");

91 sz = gme->max_size;

92 } else if (gme->max_size && sz > gme->max_size) {

93 sz = gme->max_size;

94 }

96 buf = av_malloc(sz);

97 if (!buf)

98 return AVERROR(ENOMEM);

99 sz = avio_read(pb, buf, sz);

100

101 // Data left means our buffer (the max_size option) is too small

102 if (avio_read(pb, &dummy, 1) == 1) {

103 av_log(s, AV_LOG_ERROR, "File size is larger than max_size option "

104 "value %"PRIi64", consider increasing the max_size option\n",

105 gme->max_size);

106 return AVERROR_BUFFER_TOO_SMALL;

107 }

108

109 if (gme_open_data(buf, sz, &gme->music_emu, gme->sample_rate)) {

110 av_freep(&buf);

111 return AVERROR_INVALIDDATA;

112 }

113 av_freep(&buf);

114

115 if (gme_track_info(gme->music_emu, &gme->info, gme->track_index))

116 return AVERROR_STREAM_NOT_FOUND;

117

118 if (gme_start_track(gme->music_emu, gme->track_index))

119 return AVERROR_UNKNOWN;

120

121 load_metadata(s);

122

123 st = avformat_new_stream(s, NULL);

124 if (!st)

125 return AVERROR(ENOMEM);

126 avpriv_set_pts_info(st, 64, 1, 1000);

127 if (st->duration > 0)

128 st->duration = gme->info->length;

129 st->codec->codec_type = AVMEDIA_TYPE_AUDIO;

130 st->codec->codec_id = AV_NE(AV_CODEC_ID_PCM_S16BE, AV_CODEC_ID_PCM_S16LE);

131 st->codec->channels = 2;

132 st->codec->sample_rate = gme->sample_rate;

133

134 return 0;

135 }

136

137 static int read_packet_gme(AVFormatContext *s, AVPacket *pkt)

138 {

139 GMEContext *gme = s->priv_data;

140 int n_samples = AUDIO_PKT_SIZE / 2;

141 int ret;

142

143 if (gme_track_ended(gme->music_emu))

144 return AVERROR_EOF;

145

146 if ((ret = av_new_packet(pkt, AUDIO_PKT_SIZE)) < 0)

147 return ret;

148

149 if (gme_play(gme->music_emu, n_samples, (short *)pkt->data))

150 return AVERROR_EXTERNAL;

151 pkt->size = AUDIO_PKT_SIZE;

152

153 return 0;

154 }

155

156 static int read_close_gme(AVFormatContext *s)

157 {

158 GMEContext *gme = s->priv_data;

159 gme_free_info(gme->info);

160 gme_delete(gme->music_emu);

161 return 0;

162 }

163

164 static int read_seek_gme(AVFormatContext *s, int stream_idx, int64_t ts, int flags)

165 {

166 GMEContext *gme = s->priv_data;

167 if (!gme_seek(gme->music_emu, (int)ts))

168 return AVERROR_EXTERNAL;

169 return 0;

170 }

171

172 static int probe_gme(AVProbeData *p)

173 {

174 // Reads 4 bytes - returns "" if unknown format.

175 if (gme_identify_header(p->buf)[0]) {

176 if (p->buf_size < 16384)

177 return AVPROBE_SCORE_MAX / 4 + 1;

178 else

179 return AVPROBE_SCORE_MAX / 2;

180 }

181 return 0;

182 }

183

184 static const AVClass class_gme = {

185 .class_name = "Game Music Emu demuxer",

186 .item_name = av_default_item_name,

187 .option = options,

188 .version = LIBAVUTIL_VERSION_INT,

189 };

190

191 AVInputFormat ff_libgme_demuxer = {

192 .name = "libgme",

193 .long_name = NULL_IF_CONFIG_SMALL("Game Music Emu demuxer"),

194 .priv_data_size = sizeof(GMEContext),

195 .read_probe = probe_gme,

196 .read_header = read_header_gme,

197 .read_packet = read_packet_gme,

198 .read_close = read_close_gme,

199 .read_seek = read_seek_gme,

200 .priv_class = &class_gme,

201 };

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