FFmpeg: libavcodec/msrle.c Source File

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libavcodec

msrle.c

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1 /*

2 * Microsoft RLE 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 * MS RLE video decoder by Mike Melanson (melanson@pcisys.net)

25 * For more information about the MS RLE format, visit:

26 * http://www.pcisys.net/~melanson/codecs/

27 *

28 * The MS RLE decoder outputs PAL8 colorspace data.

29 */

31 #include <stdio.h>

32 #include <stdlib.h>

33 #include <string.h>

35 #include "avcodec.h"

36 #include "internal.h"

37 #include "msrledec.h"

38 #include "libavutil/imgutils.h"

40 typedef struct MsrleContext {

41 AVCodecContext *avctx;

42 AVFrame *frame;

44 GetByteContext gb;

45 const unsigned char *buf;

46 int size;

48 uint32_t pal[256];

49 } MsrleContext;

51 static av_cold int msrle_decode_init(AVCodecContext *avctx)

52 {

53 MsrleContext *s = avctx->priv_data;

54 int i;

56 s->avctx = avctx;

58 switch (avctx->bits_per_coded_sample) {

59 case 1:

60 avctx->pix_fmt = AV_PIX_FMT_MONOWHITE;

61 break;

62 case 4:

63 case 8:

64 avctx->pix_fmt = AV_PIX_FMT_PAL8;

65 break;

66 case 24:

67 avctx->pix_fmt = AV_PIX_FMT_BGR24;

68 break;

69 default:

70 av_log(avctx, AV_LOG_ERROR, "unsupported bits per sample\n");

71 return AVERROR_INVALIDDATA;

72 }

74 s->frame = av_frame_alloc();

75 if (!s->frame)

76 return AVERROR(ENOMEM);

78 if (avctx->extradata_size >= 4)

79 for (i = 0; i < FFMIN(avctx->extradata_size, AVPALETTE_SIZE)/4; i++)

80 s->pal[i] = 0xFFU<<24 | AV_RL32(avctx->extradata+4*i);

82 return 0;

83 }

85 static int msrle_decode_frame(AVCodecContext *avctx,

86 void *data, int *got_frame,

87 AVPacket *avpkt)

88 {

89 const uint8_t *buf = avpkt->data;

90 int buf_size = avpkt->size;

91 MsrleContext *s = avctx->priv_data;

92 int istride = FFALIGN(avctx->width*avctx->bits_per_coded_sample, 32) / 8;

93 int ret;

95 s->buf = buf;

96 s->size = buf_size;

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

99 return ret;

100

101 if (avctx->bits_per_coded_sample > 1 && avctx->bits_per_coded_sample <= 8) {

102 const uint8_t *pal = av_packet_get_side_data(avpkt, AV_PKT_DATA_PALETTE, NULL);

103

104 if (pal) {

105 s->frame->palette_has_changed = 1;

106 memcpy(s->pal, pal, AVPALETTE_SIZE);

107 }

108 /* make the palette available */

109 memcpy(s->frame->data[1], s->pal, AVPALETTE_SIZE);

110 }

111

112 /* FIXME how to correctly detect RLE ??? */

113 if (avctx->height * istride == avpkt->size) { /* assume uncompressed */

114 int linesize = av_image_get_linesize(avctx->pix_fmt, avctx->width, 0);

115 uint8_t *ptr = s->frame->data[0];

116 uint8_t *buf = avpkt->data + (avctx->height-1)*istride;

117 int i, j;

118

119 if (linesize < 0)

120 return linesize;

121

122 for (i = 0; i < avctx->height; i++) {

123 if (avctx->bits_per_coded_sample == 4) {

124 for (j = 0; j < avctx->width - 1; j += 2) {

125 ptr[j+0] = buf[j>>1] >> 4;

126 ptr[j+1] = buf[j>>1] & 0xF;

127 }

128 if (avctx->width & 1)

129 ptr[j+0] = buf[j>>1] >> 4;

130 } else {

131 memcpy(ptr, buf, linesize);

132 }

133 buf -= istride;

134 ptr += s->frame->linesize[0];

135 }

136 } else {

137 bytestream2_init(&s->gb, buf, buf_size);

138 ff_msrle_decode(avctx, (AVPicture*)s->frame, avctx->bits_per_coded_sample, &s->gb);

139 }

140

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

142 return ret;

143

144 *got_frame = 1;

145

146 /* report that the buffer was completely consumed */

147 return buf_size;

148 }

149

150 static av_cold int msrle_decode_end(AVCodecContext *avctx)

151 {

152 MsrleContext *s = avctx->priv_data;

153

154 /* release the last frame */

155 av_frame_free(&s->frame);

156

157 return 0;

158 }

159

160 AVCodec ff_msrle_decoder = {

161 .name = "msrle",

162 .long_name = NULL_IF_CONFIG_SMALL("Microsoft RLE"),

163 .type = AVMEDIA_TYPE_VIDEO,

164 .id = AV_CODEC_ID_MSRLE,

165 .priv_data_size = sizeof(MsrleContext),

166 .init = msrle_decode_init,

167 .close = msrle_decode_end,

168 .decode = msrle_decode_frame,

169 .capabilities = CODEC_CAP_DR1,

170 };

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