FFmpeg: libavformat/dxa.c Source File

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libavformat

dxa.c

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1 /*

2 * DXA 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 "libavutil/intreadwrite.h"

23 #include "avformat.h"

24 #include "internal.h"

25 #include "riff.h"

27 #define DXA_EXTRA_SIZE 9

29 typedef struct{

30 int frames;

31 int has_sound;

32 int bpc;

33 uint32_t bytes_left;

34 int64_t wavpos, vidpos;

35 int readvid;

36 }DXAContext;

38 static int dxa_probe(AVProbeData *p)

39 {

40 int w, h;

41 if (p->buf_size < 15)

42 return 0;

43 w = AV_RB16(p->buf + 11);

44 h = AV_RB16(p->buf + 13);

45 /* check file header */

46 if (p->buf[0] == 'D' && p->buf[1] == 'E' &&

47 p->buf[2] == 'X' && p->buf[3] == 'A' &&

48 w && w <= 2048 && h && h <= 2048)

49 return AVPROBE_SCORE_MAX;

50 else

51 return 0;

52 }

54 static int dxa_read_header(AVFormatContext *s)

55 {

56 AVIOContext *pb = s->pb;

57 DXAContext *c = s->priv_data;

58 AVStream *st, *ast;

59 uint32_t tag;

60 int32_t fps;

61 int w, h;

62 int num, den;

63 int flags;

64 int ret;

66 tag = avio_rl32(pb);

67 if (tag != MKTAG('D', 'E', 'X', 'A'))

68 return AVERROR_INVALIDDATA;

69 flags = avio_r8(pb);

70 c->frames = avio_rb16(pb);

71 if(!c->frames){

72 av_log(s, AV_LOG_ERROR, "File contains no frames ???\n");

73 return AVERROR_INVALIDDATA;

74 }

76 fps = avio_rb32(pb);

77 if(fps > 0){

78 den = 1000;

79 num = fps;

80 }else if (fps < 0){

81 den = 100000;

82 num = -fps;

83 }else{

84 den = 10;

85 num = 1;

86 }

87 w = avio_rb16(pb);

88 h = avio_rb16(pb);

89 c->has_sound = 0;

91 st = avformat_new_stream(s, NULL);

92 if (!st)

93 return AVERROR(ENOMEM);

95 // Parse WAV data header

96 if(avio_rl32(pb) == MKTAG('W', 'A', 'V', 'E')){

97 uint32_t size, fsize;

98 c->has_sound = 1;

99 size = avio_rb32(pb);

100 c->vidpos = avio_tell(pb) + size;

101 avio_skip(pb, 16);

102 fsize = avio_rl32(pb);

103

104 ast = avformat_new_stream(s, NULL);

105 if (!ast)

106 return AVERROR(ENOMEM);

107 ret = ff_get_wav_header(pb, ast->codec, fsize);

108 if (ret < 0)

109 return ret;

110 if (ast->codec->sample_rate > 0)

111 avpriv_set_pts_info(ast, 64, 1, ast->codec->sample_rate);

112 // find 'data' chunk

113 while(avio_tell(pb) < c->vidpos && !url_feof(pb)){

114 tag = avio_rl32(pb);

115 fsize = avio_rl32(pb);

116 if(tag == MKTAG('d', 'a', 't', 'a')) break;

117 avio_skip(pb, fsize);

118 }

119 c->bpc = (fsize + c->frames - 1) / c->frames;

120 if(ast->codec->block_align)

121 c->bpc = ((c->bpc + ast->codec->block_align - 1) / ast->codec->block_align) * ast->codec->block_align;

122 c->bytes_left = fsize;

123 c->wavpos = avio_tell(pb);

124 avio_seek(pb, c->vidpos, SEEK_SET);

125 }

126

127 /* now we are ready: build format streams */

128 st->codec->codec_type = AVMEDIA_TYPE_VIDEO;

129 st->codec->codec_id = AV_CODEC_ID_DXA;

130 st->codec->width = w;

131 st->codec->height = h;

132 av_reduce(&den, &num, den, num, (1UL<<31)-1);

133 avpriv_set_pts_info(st, 33, num, den);

134 /* flags & 0x80 means that image is interlaced,

135 * flags & 0x40 means that image has double height

136 * either way set true height

137 */

138 if(flags & 0xC0){

139 st->codec->height >>= 1;

140 }

141 c->readvid = !c->has_sound;

142 c->vidpos = avio_tell(pb);

143 s->start_time = 0;

144 s->duration = (int64_t)c->frames * AV_TIME_BASE * num / den;

145 av_log(s, AV_LOG_DEBUG, "%d frame(s)\n",c->frames);

146

147 return 0;

148 }

149

150 static int dxa_read_packet(AVFormatContext *s, AVPacket *pkt)

151 {

152 DXAContext *c = s->priv_data;

153 int ret;

154 uint32_t size;

155 uint8_t buf[DXA_EXTRA_SIZE], pal[768+4];

156 int pal_size = 0;

157

158 if(!c->readvid && c->has_sound && c->bytes_left){

159 c->readvid = 1;

160 avio_seek(s->pb, c->wavpos, SEEK_SET);

161 size = FFMIN(c->bytes_left, c->bpc);

162 ret = av_get_packet(s->pb, pkt, size);

163 pkt->stream_index = 1;

164 if(ret != size)

165 return AVERROR(EIO);

166 c->bytes_left -= size;

167 c->wavpos = avio_tell(s->pb);

168 return 0;

169 }

170 avio_seek(s->pb, c->vidpos, SEEK_SET);

171 while(!url_feof(s->pb) && c->frames){

172 avio_read(s->pb, buf, 4);

173 switch(AV_RL32(buf)){

174 case MKTAG('N', 'U', 'L', 'L'):

175 if(av_new_packet(pkt, 4 + pal_size) < 0)

176 return AVERROR(ENOMEM);

177 pkt->stream_index = 0;

178 if(pal_size) memcpy(pkt->data, pal, pal_size);

179 memcpy(pkt->data + pal_size, buf, 4);

180 c->frames--;

181 c->vidpos = avio_tell(s->pb);

182 c->readvid = 0;

183 return 0;

184 case MKTAG('C', 'M', 'A', 'P'):

185 pal_size = 768+4;

186 memcpy(pal, buf, 4);

187 avio_read(s->pb, pal + 4, 768);

188 break;

189 case MKTAG('F', 'R', 'A', 'M'):

190 avio_read(s->pb, buf + 4, DXA_EXTRA_SIZE - 4);

191 size = AV_RB32(buf + 5);

192 if(size > 0xFFFFFF){

193 av_log(s, AV_LOG_ERROR, "Frame size is too big: %d\n", size);

194 return AVERROR_INVALIDDATA;

195 }

196 if(av_new_packet(pkt, size + DXA_EXTRA_SIZE + pal_size) < 0)

197 return AVERROR(ENOMEM);

198 memcpy(pkt->data + pal_size, buf, DXA_EXTRA_SIZE);

199 ret = avio_read(s->pb, pkt->data + DXA_EXTRA_SIZE + pal_size, size);

200 if(ret != size){

201 av_free_packet(pkt);

202 return AVERROR(EIO);

203 }

204 if(pal_size) memcpy(pkt->data, pal, pal_size);

205 pkt->stream_index = 0;

206 c->frames--;

207 c->vidpos = avio_tell(s->pb);

208 c->readvid = 0;

209 return 0;

210 default:

211 av_log(s, AV_LOG_ERROR, "Unknown tag %c%c%c%c\n", buf[0], buf[1], buf[2], buf[3]);

212 return AVERROR_INVALIDDATA;

213 }

214 }

215 return AVERROR_EOF;

216 }

217

218 AVInputFormat ff_dxa_demuxer = {

219 .name = "dxa",

220 .long_name = NULL_IF_CONFIG_SMALL("DXA"),

221 .priv_data_size = sizeof(DXAContext),

222 .read_probe = dxa_probe,

223 .read_header = dxa_read_header,

224 .read_packet = dxa_read_packet,

225 };

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