FFmpeg: libavformat/icodec.c Source File

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libavformat

icodec.c

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1 /*

2 * Microsoft Windows ICO 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 * Microsoft Windows ICO demuxer

25 */

27 #include "libavutil/intreadwrite.h"

28 #include "libavcodec/bytestream.h"

29 #include "libavcodec/bmp.h"

30 #include "avformat.h"

31 #include "internal.h"

33 typedef struct {

34 int offset;

35 int size;

36 int nb_pal;

37 } IcoImage;

39 typedef struct {

40 int current_image;

41 int nb_images;

42 IcoImage * images;

43 } IcoDemuxContext;

45 static int probe(AVProbeData *p)

46 {

47 if (AV_RL16(p->buf) == 0 && AV_RL16(p->buf + 2) == 1 && AV_RL16(p->buf + 4))

48 return AVPROBE_SCORE_MAX / 3;

49 return 0;

50 }

52 static int read_header(AVFormatContext *s)

53 {

54 IcoDemuxContext *ico = s->priv_data;

55 AVIOContext *pb = s->pb;

56 int i, codec;

58 avio_skip(pb, 4);

59 ico->nb_images = avio_rl16(pb);

61 ico->images = av_malloc(ico->nb_images * sizeof(IcoImage));

62 if (!ico->images)

63 return AVERROR(ENOMEM);

65 for (i = 0; i < ico->nb_images; i++) {

66 AVStream *st;

67 int tmp;

69 if (avio_seek(pb, 6 + i * 16, SEEK_SET) < 0)

70 break;

72 st = avformat_new_stream(s, NULL);

73 if (!st)

74 return AVERROR(ENOMEM);

76 st->codec->codec_type = AVMEDIA_TYPE_VIDEO;

77 st->codec->width = avio_r8(pb);

78 st->codec->height = avio_r8(pb);

79 ico->images[i].nb_pal = avio_r8(pb);

80 if (ico->images[i].nb_pal == 255)

81 ico->images[i].nb_pal = 0;

83 avio_skip(pb, 5);

85 ico->images[i].size = avio_rl32(pb);

86 ico->images[i].offset = avio_rl32(pb);

88 if (avio_seek(pb, ico->images[i].offset, SEEK_SET) < 0)

89 break;

91 codec = avio_rl32(pb);

92 switch (codec) {

93 case MKTAG(0x89, 'P', 'N', 'G'):

94 st->codec->codec_id = AV_CODEC_ID_PNG;

95 st->codec->width = 0;

96 st->codec->height = 0;

97 break;

98 case 40:

99 if (ico->images[i].size < 40)

100 return AVERROR_INVALIDDATA;

101 st->codec->codec_id = AV_CODEC_ID_BMP;

102 tmp = avio_rl32(pb);

103 if (tmp)

104 st->codec->width = tmp;

105 tmp = avio_rl32(pb);

106 if (tmp)

107 st->codec->height = tmp / 2;

108 break;

109 default:

110 avpriv_request_sample(s, "codec %d", codec);

111 return AVERROR_INVALIDDATA;

112 }

113 }

114

115 return 0;

116 }

117

118 static int read_packet(AVFormatContext *s, AVPacket *pkt)

119 {

120 IcoDemuxContext *ico = s->priv_data;

121 IcoImage *image;

122 AVIOContext *pb = s->pb;

123 AVStream *st = s->streams[0];

124 int ret;

125

126 if (ico->current_image >= ico->nb_images)

127 return AVERROR(EIO);

128

129 image = &ico->images[ico->current_image];

130

131 if ((ret = avio_seek(pb, image->offset, SEEK_SET)) < 0)

132 return ret;

133

134 if (s->streams[ico->current_image]->codec->codec_id == AV_CODEC_ID_PNG) {

135 if ((ret = av_get_packet(pb, pkt, image->size)) < 0)

136 return ret;

137 } else {

138 uint8_t *buf;

139 if ((ret = av_new_packet(pkt, 14 + image->size)) < 0)

140 return ret;

141 buf = pkt->data;

142

143 /* add BMP header */

144 bytestream_put_byte(&buf, 'B');

145 bytestream_put_byte(&buf, 'M');

146 bytestream_put_le32(&buf, pkt->size);

147 bytestream_put_le16(&buf, 0);

148 bytestream_put_le16(&buf, 0);

149 bytestream_put_le32(&buf, 0);

150

151 if ((ret = avio_read(pb, buf, image->size)) < 0)

152 return ret;

153

154 st->codec->bits_per_coded_sample = AV_RL16(buf + 14);

155

156 if (AV_RL32(buf + 32))

157 image->nb_pal = AV_RL32(buf + 32);

158

159 if (st->codec->bits_per_coded_sample <= 8 && !image->nb_pal) {

160 image->nb_pal = 1 << st->codec->bits_per_coded_sample;

161 AV_WL32(buf + 32, image->nb_pal);

162 }

163

164 AV_WL32(buf - 4, 14 + 40 + image->nb_pal * 4);

165 AV_WL32(buf + 8, AV_RL32(buf + 8) / 2);

166 }

167

168 pkt->stream_index = ico->current_image++;

169 pkt->flags |= AV_PKT_FLAG_KEY;

170

171 return 0;

172 }

173

174 AVInputFormat ff_ico_demuxer = {

175 .name = "ico",

176 .long_name = NULL_IF_CONFIG_SMALL("Microsoft Windows ICO"),

177 .priv_data_size = sizeof(IcoDemuxContext),

178 .read_probe = probe,

179 .read_header = read_header,

180 .read_packet = read_packet,

181 .flags = AVFMT_NOTIMESTAMPS,

182 };

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