FFmpeg: libavformat/redspark.c Source File

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libavformat

redspark.c

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1 /*

2 * RedSpark 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 #include "libavcodec/bytestream.h"

23 #include "libavutil/intreadwrite.h"

24 #include "avformat.h"

25 #include "avio.h"

26 #include "internal.h"

28 #define HEADER_SIZE 4096

30 typedef struct RedSparkContext {

31 int samples_count;

32 } RedSparkContext;

34 static int redspark_probe(AVProbeData *p)

35 {

36 uint32_t key, data;

37 uint8_t header[8];

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);

45 data = AV_RB32(p->buf + 4) ^ (((key << 3) | (key >> 29)) + key);

46 AV_WB32(header + 4, data);

48 if (AV_RB64(header) == AV_RB64("RedSpark"))

49 return AVPROBE_SCORE_MAX;

51 return 0;

52 }

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;

65 st = avformat_new_stream(s, NULL);

66 if (!st)

67 return AVERROR(ENOMEM);

68 codec = st->codec;

70 header = av_malloc(HEADER_SIZE + FF_INPUT_BUFFER_PADDING_SIZE);

71 if (!header)

72 return AVERROR(ENOMEM);

73 pbc = header;

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);

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 }

86 codec->codec_id = AV_CODEC_ID_ADPCM_THP;

87 codec->codec_type = AVMEDIA_TYPE_AUDIO;

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 }

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 };

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