FFmpeg: libavcodec/assdec.c Source File

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libavcodec

assdec.c

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1 /*

2 * SSA/ASS decoder

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 <string.h>

24 #include "avcodec.h"

25 #include "ass.h"

26 #include "ass_split.h"

27 #include "libavutil/internal.h"

28 #include "libavutil/mem.h"

30 static av_cold int ass_decode_init(AVCodecContext *avctx)

31 {

32 avctx->subtitle_header = av_malloc(avctx->extradata_size + 1);

33 if (!avctx->subtitle_header)

34 return AVERROR(ENOMEM);

35 memcpy(avctx->subtitle_header, avctx->extradata, avctx->extradata_size);

36 avctx->subtitle_header[avctx->extradata_size] = 0;

37 avctx->subtitle_header_size = avctx->extradata_size;

38 avctx->priv_data = ff_ass_split(avctx->extradata);

39 if(!avctx->priv_data)

40 return -1;

41 return 0;

42 }

44 static int ass_decode_close(AVCodecContext *avctx)

45 {

46 ff_ass_split_free(avctx->priv_data);

47 avctx->priv_data = NULL;

48 return 0;

49 }

51 #if CONFIG_SSA_DECODER

52 static int ssa_decode_frame(AVCodecContext *avctx, void *data, int *got_sub_ptr,

53 AVPacket *avpkt)

54 {

55 const char *ptr = avpkt->data;

56 int len, size = avpkt->size;

58 while (size > 0) {

59 int duration;

60 ASSDialog *dialog = ff_ass_split_dialog(avctx->priv_data, ptr, 0, NULL);

61 if (!dialog)

62 return AVERROR_INVALIDDATA;

63 duration = dialog->end - dialog->start;

64 len = ff_ass_add_rect(data, ptr, 0, duration, 1);

65 if (len < 0)

66 return len;

67 ptr += len;

68 size -= len;

69 }

71 *got_sub_ptr = avpkt->size > 0;

72 return avpkt->size;

73 }

75 AVCodec ff_ssa_decoder = {

76 .name = "ssa",

77 .long_name = NULL_IF_CONFIG_SMALL("SSA (SubStation Alpha) subtitle"),

78 .type = AVMEDIA_TYPE_SUBTITLE,

79 .id = AV_CODEC_ID_SSA,

80 .init = ass_decode_init,

81 .decode = ssa_decode_frame,

82 .close = ass_decode_close,

83 };

84 #endif

86 #if CONFIG_ASS_DECODER

87 static int ass_decode_frame(AVCodecContext *avctx, void *data, int *got_sub_ptr,

88 AVPacket *avpkt)

89 {

90 int ret;

91 AVSubtitle *sub = data;

92 const char *ptr = avpkt->data;

93 static const AVRational ass_tb = {1, 100};

94 const int ts_start = av_rescale_q(avpkt->pts, avctx->time_base, ass_tb);

95 const int ts_duration = av_rescale_q(avpkt->duration, avctx->time_base, ass_tb);

97 if (avpkt->size <= 0)

98 return avpkt->size;

100 ret = ff_ass_add_rect(sub, ptr, ts_start, ts_duration, 2);

101 if (ret < 0) {

102 if (ret == AVERROR_INVALIDDATA)

103 av_log(avctx, AV_LOG_ERROR, "Invalid ASS packet\n");

104 return ret;

105 }

106

107 *got_sub_ptr = avpkt->size > 0;

108 return avpkt->size;

109 }

110

111 AVCodec ff_ass_decoder = {

112 .name = "ass",

113 .long_name = NULL_IF_CONFIG_SMALL("ASS (Advanced SubStation Alpha) subtitle"),

114 .type = AVMEDIA_TYPE_SUBTITLE,

115 .id = AV_CODEC_ID_ASS,

116 .init = ass_decode_init,

117 .decode = ass_decode_frame,

118 .close = ass_decode_close,

119 };

120 #endif

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