FFmpeg: libavcodec/mjpeg2jpeg_bsf.c Source File

FFmpeg

[フレーム]

libavcodec

mjpeg2jpeg_bsf.c

Go to the documentation of this file.

1 /*

2 * MJPEG/AVI1 to JPEG/JFIF bitstream format filter

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 * Adapted from mjpeg2jpeg.c, with original copyright:

24 * Paris 2010 Adrian Daerr, public domain

25 */

27 #include <string.h>

28 #include "avcodec.h"

29 #include "mjpeg.h"

31 static const uint8_t jpeg_header[] = {

32 0xff, 0xd8, // SOI

33 0xff, 0xe0, // APP0

34 0x00, 0x10, // APP0 header size (including

35 // this field, but excluding preceding)

36 0x4a, 0x46, 0x49, 0x46, 0x00, // ID string 'JFIF0円'

37 0x01, 0x01, // version

38 0x00, // bits per type

39 0x00, 0x00, // X density

40 0x00, 0x00, // Y density

41 0x00, // X thumbnail size

42 0x00, // Y thumbnail size

43 };

45 static const int dht_segment_size = 420;

46 static const uint8_t dht_segment_head[] = { 0xFF, 0xC4, 0x01, 0xA2, 0x00 };

47 static const uint8_t dht_segment_frag[] = {

48 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09,

49 0x0a, 0x0b, 0x01, 0x00, 0x03, 0x01, 0x01, 0x01, 0x01, 0x01,

50 0x01, 0x01, 0x01, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00,

51 };

53 static uint8_t *append(uint8_t *buf, const uint8_t *src, int size)

54 {

55 memcpy(buf, src, size);

56 return buf + size;

57 }

59 static uint8_t *append_dht_segment(uint8_t *buf)

60 {

61 buf = append(buf, dht_segment_head, sizeof(dht_segment_head));

62 buf = append(buf, avpriv_mjpeg_bits_dc_luminance + 1, 16);

63 buf = append(buf, dht_segment_frag, sizeof(dht_segment_frag));

64 buf = append(buf, avpriv_mjpeg_val_dc, 12);

65 *(buf++) = 0x10;

66 buf = append(buf, avpriv_mjpeg_bits_ac_luminance + 1, 16);

67 buf = append(buf, avpriv_mjpeg_val_ac_luminance, 162);

68 *(buf++) = 0x11;

69 buf = append(buf, avpriv_mjpeg_bits_ac_chrominance + 1, 16);

70 buf = append(buf, avpriv_mjpeg_val_ac_chrominance, 162);

71 return buf;

72 }

74 static int mjpeg2jpeg_filter(AVBitStreamFilterContext *bsfc,

75 AVCodecContext *avctx, const char *args,

76 uint8_t **poutbuf, int *poutbuf_size,

77 const uint8_t *buf, int buf_size,

78 int keyframe)

79 {

80 int input_skip, output_size;

81 uint8_t *output, *out;

83 if (buf_size < 12) {

84 av_log(avctx, AV_LOG_ERROR, "input is truncated\n");

85 return AVERROR_INVALIDDATA;

86 }

87 if (memcmp("AVI1", buf + 6, 4)) {

88 av_log(avctx, AV_LOG_ERROR, "input is not MJPEG/AVI1\n");

89 return AVERROR_INVALIDDATA;

90 }

91 input_skip = (buf[4] << 8) + buf[5] + 4;

92 if (buf_size < input_skip) {

93 av_log(avctx, AV_LOG_ERROR, "input is truncated\n");

94 return AVERROR_INVALIDDATA;

95 }

96 output_size = buf_size - input_skip +

97 sizeof(jpeg_header) + dht_segment_size;

98 output = out = av_malloc(output_size);

99 if (!output)

100 return AVERROR(ENOMEM);

101 out = append(out, jpeg_header, sizeof(jpeg_header));

102 out = append_dht_segment(out);

103 out = append(out, buf + input_skip, buf_size - input_skip);

104 *poutbuf = output;

105 *poutbuf_size = output_size;

106 return 1;

107 }

108

109 AVBitStreamFilter ff_mjpeg2jpeg_bsf = {

110 .name = "mjpeg2jpeg",

111 .filter = mjpeg2jpeg_filter,

112 };

Generated on Wed Jul 10 2013 23:48:01 for FFmpeg by doxygen 1.8.2