FFmpeg: libavcodec/sgirledec.c Source File

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libavcodec

sgirledec.c

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1 /*

2 * SGI RLE 8-bit 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 /**

23 * @file

24 * SGI RLE 8-bit decoder

25 */

27 #include "avcodec.h"

28 #include "internal.h"

30 typedef struct SGIRLEContext {

31 AVFrame *frame;

32 } SGIRLEContext;

34 static av_cold int sgirle_decode_init(AVCodecContext *avctx)

35 {

36 SGIRLEContext *s = avctx->priv_data;

37 avctx->pix_fmt = AV_PIX_FMT_BGR8;

38 s->frame = av_frame_alloc();

39 if (!s->frame)

40 return AVERROR(ENOMEM);

41 return 0;

42 }

44 /**

45 * Convert SGI RGB332 pixel into AV_PIX_FMT_BGR8

46 * SGI RGB332 is packed RGB 3:3:2, 8bpp, (msb)3R 2B 3G(lsb)

47 */

48 #define RGB332_TO_BGR8(x) (((x << 3) & 0xC0) | ((x << 3) & 0x38) | ((x >> 5) & 7))

50 static av_always_inline void memcpy_rgb332_to_bgr8(uint8_t *dst, const uint8_t *src, int size)

51 {

52 int i;

53 for (i = 0; i < size; i++)

54 dst[i] = RGB332_TO_BGR8(src[i]);

55 }

57 /**

58 * @param[out] dst Destination buffer

59 * @param[in] src Source buffer

60 * @param src_size Source buffer size (bytes)

61 * @param width Width of destination buffer (pixels)

62 * @param height Height of destination buffer (pixels)

63 * @param linesize Line size of destination buffer (bytes)

64 * @return <0 on error

65 */

66 static int decode_sgirle8(AVCodecContext *avctx, uint8_t *dst, const uint8_t *src, int src_size, int width, int height, int linesize)

67 {

68 const uint8_t *src_end = src + src_size;

69 int x = 0, y = 0;

71 #define INC_XY(n) \

72 x += n; \

73 if (x >= width) { \

74 y++; \

75 if (y >= height) \

76 return 0; \

77 x = 0; \

78 }

80 while (src_end - src >= 2) {

81 uint8_t v = *src++;

82 if (v > 0 && v < 0xC0) {

83 do {

84 int length = FFMIN(v, width - x);

85 memset(dst + y*linesize + x, RGB332_TO_BGR8(*src), length);

86 INC_XY(length);

87 v -= length;

88 } while (v > 0);

89 src++;

90 } else if (v >= 0xC1) {

91 v -= 0xC0;

92 do {

93 int length = FFMIN3(v, width - x, src_end - src);

94 if (src_end - src < length)

95 break;

96 memcpy_rgb332_to_bgr8(dst + y*linesize + x, src, length);

97 INC_XY(length);

98 src += length;

99 v -= length;

100 } while (v > 0);

101 } else {

102 avpriv_request_sample(avctx, "opcode %d", v);

103 return AVERROR_PATCHWELCOME;

104 }

105 }

106 return 0;

107 }

108

109 static int sgirle_decode_frame(AVCodecContext *avctx,

110 void *data, int *got_frame,

111 AVPacket *avpkt)

112 {

113 SGIRLEContext *s = avctx->priv_data;

114 int ret;

115

116 if ((ret = ff_reget_buffer(avctx, s->frame)) < 0)

117 return ret;

118

119 ret = decode_sgirle8(avctx, s->frame->data[0], avpkt->data, avpkt->size, avctx->width, avctx->height, s->frame->linesize[0]);

120 if (ret < 0)

121 return ret;

122

123 *got_frame = 1;

124 if ((ret = av_frame_ref(data, s->frame)) < 0)

125 return ret;

126

127 return avpkt->size;

128 }

129

130 static av_cold int sgirle_decode_end(AVCodecContext *avctx)

131 {

132 SGIRLEContext *s = avctx->priv_data;

133

134 av_frame_free(&s->frame);

135

136 return 0;

137 }

138

139 AVCodec ff_sgirle_decoder = {

140 .name = "sgirle",

141 .type = AVMEDIA_TYPE_VIDEO,

142 .id = AV_CODEC_ID_SGIRLE,

143 .priv_data_size = sizeof(SGIRLEContext),

144 .init = sgirle_decode_init,

145 .close = sgirle_decode_end,

146 .decode = sgirle_decode_frame,

147 .capabilities = CODEC_CAP_DR1,

148 .long_name = NULL_IF_CONFIG_SMALL("SGI RLE 8-bit"),

149 };

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