FFmpeg: libavcodec/bfi.c Source File

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libavcodec

bfi.c

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1 /*

2 * Brute Force & Ignorance (BFI) video 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 * @brief Brute Force & Ignorance (.bfi) video decoder

25 * @author Sisir Koppaka ( sisir.koppaka at gmail dot com )

26 * @see http://wiki.multimedia.cx/index.php?title=BFI

27 */

29 #include "libavutil/common.h"

30 #include "avcodec.h"

31 #include "bytestream.h"

32 #include "internal.h"

34 typedef struct BFIContext {

35 AVCodecContext *avctx;

36 uint8_t *dst;

37 uint32_t pal[256];

38 } BFIContext;

40 static av_cold int bfi_decode_init(AVCodecContext *avctx)

41 {

42 BFIContext *bfi = avctx->priv_data;

43 avctx->pix_fmt = AV_PIX_FMT_PAL8;

44 bfi->dst = av_mallocz(avctx->width * avctx->height);

45 if (!bfi->dst)

46 return AVERROR(ENOMEM);

47 return 0;

48 }

50 static int bfi_decode_frame(AVCodecContext *avctx, void *data,

51 int *got_frame, AVPacket *avpkt)

52 {

53 AVFrame *frame = data;

54 GetByteContext g;

55 int buf_size = avpkt->size;

56 BFIContext *bfi = avctx->priv_data;

57 uint8_t *dst = bfi->dst;

58 uint8_t *src, *dst_offset, colour1, colour2;

59 uint8_t *frame_end = bfi->dst + avctx->width * avctx->height;

60 uint32_t *pal;

61 int i, j, ret, height = avctx->height;

63 if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)

64 return ret;

66 bytestream2_init(&g, avpkt->data, buf_size);

68 /* Set frame parameters and palette, if necessary */

69 if (!avctx->frame_number) {

70 frame->pict_type = AV_PICTURE_TYPE_I;

71 frame->key_frame = 1;

72 /* Setting the palette */

73 if (avctx->extradata_size > 768) {

74 av_log(NULL, AV_LOG_ERROR, "Palette is too large.\n");

75 return AVERROR_INVALIDDATA;

76 }

77 pal = (uint32_t *)frame->data[1];

78 for (i = 0; i < avctx->extradata_size / 3; i++) {

79 int shift = 16;

80 *pal = 0xFFU << 24;

81 for (j = 0; j < 3; j++, shift -= 8)

82 *pal += ((avctx->extradata[i * 3 + j] << 2) |

83 (avctx->extradata[i * 3 + j] >> 4)) << shift;

84 pal++;

85 }

86 memcpy(bfi->pal, frame->data[1], sizeof(bfi->pal));

87 frame->palette_has_changed = 1;

88 } else {

89 frame->pict_type = AV_PICTURE_TYPE_P;

90 frame->key_frame = 0;

91 frame->palette_has_changed = 0;

92 memcpy(frame->data[1], bfi->pal, sizeof(bfi->pal));

93 }

95 bytestream2_skip(&g, 4); // Unpacked size, not required.

97 while (dst != frame_end) {

98 static const uint8_t lentab[4] = { 0, 2, 0, 1 };

99 unsigned int byte = bytestream2_get_byte(&g), av_uninit(offset);

100 unsigned int code = byte >> 6;

101 unsigned int length = byte & ~0xC0;

102

103 if (!bytestream2_get_bytes_left(&g)) {

104 av_log(avctx, AV_LOG_ERROR,

105 "Input resolution larger than actual frame.\n");

106 return AVERROR_INVALIDDATA;

107 }

108

109 /* Get length and offset (if required) */

110 if (length == 0) {

111 if (code == 1) {

112 length = bytestream2_get_byte(&g);

113 offset = bytestream2_get_le16(&g);

114 } else {

115 length = bytestream2_get_le16(&g);

116 if (code == 2 && length == 0)

117 break;

118 }

119 } else {

120 if (code == 1)

121 offset = bytestream2_get_byte(&g);

122 }

123

124 /* Do boundary check */

125 if (dst + (length << lentab[code]) > frame_end)

126 break;

127

128 switch (code) {

129 case 0: // normal chain

130 if (length >= bytestream2_get_bytes_left(&g)) {

131 av_log(avctx, AV_LOG_ERROR, "Frame larger than buffer.\n");

132 return AVERROR_INVALIDDATA;

133 }

134 bytestream2_get_buffer(&g, dst, length);

135 dst += length;

136 break;

137 case 1: // back chain

138 dst_offset = dst - offset;

139 length *= 4; // Convert dwords to bytes.

140 if (dst_offset < bfi->dst)

141 break;

142 while (length--)

143 *dst++ = *dst_offset++;

144 break;

145 case 2: // skip chain

146 dst += length;

147 break;

148 case 3: // fill chain

149 colour1 = bytestream2_get_byte(&g);

150 colour2 = bytestream2_get_byte(&g);

151 while (length--) {

152 *dst++ = colour1;

153 *dst++ = colour2;

154 }

155 break;

156 }

157 }

158

159 src = bfi->dst;

160 dst = frame->data[0];

161 while (height--) {

162 memcpy(dst, src, avctx->width);

163 src += avctx->width;

164 dst += frame->linesize[0];

165 }

166 *got_frame = 1;

167

168 return buf_size;

169 }

170

171 static av_cold int bfi_decode_close(AVCodecContext *avctx)

172 {

173 BFIContext *bfi = avctx->priv_data;

174 av_freep(&bfi->dst);

175 return 0;

176 }

177

178 AVCodec ff_bfi_decoder = {

179 .name = "bfi",

180 .long_name = NULL_IF_CONFIG_SMALL("Brute Force & Ignorance"),

181 .type = AVMEDIA_TYPE_VIDEO,

182 .id = AV_CODEC_ID_BFI,

183 .priv_data_size = sizeof(BFIContext),

184 .init = bfi_decode_init,

185 .close = bfi_decode_close,

186 .decode = bfi_decode_frame,

187 .capabilities = CODEC_CAP_DR1,

188 };

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