FFmpeg: libavcodec/bfi.c Source File

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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(avctx, 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 const 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 = AV_CODEC_CAP_DR1,

188 .caps_internal = FF_CODEC_CAP_INIT_THREADSAFE,

189 };

AVCodec

AVCodec.

Definition: codec.h:202

FF_CODEC_CAP_INIT_THREADSAFE

#define FF_CODEC_CAP_INIT_THREADSAFE

The codec does not modify any global variables in the init function, allowing to call the init functi...

Definition: internal.h:42

AVERROR

Filter the word "frame" indicates either a video frame or a group of audio as stored in an AVFrame structure Format for each input and each output the list of supported formats For video that means pixel format For audio that means channel sample they are references to shared objects When the negotiation mechanism computes the intersection of the formats supported at each end of a all references to both lists are replaced with a reference to the intersection And when a single format is eventually chosen for a link amongst the remaining all references to the list are updated That means that if a filter requires that its input and output have the same format amongst a supported all it has to do is use a reference to the same list of formats query_formats can leave some formats unset and return AVERROR(EAGAIN) to cause the negotiation mechanism toagain later. That can be used by filters with complex requirements to use the format negotiated on one link to set the formats supported on another. Frame references ownership and permissions

GetByteContext

Definition: bytestream.h:33

bfi_decode_close

static av_cold int bfi_decode_close(AVCodecContext *avctx)

Definition: bfi.c:171

ff_bfi_decoder

const AVCodec ff_bfi_decoder

Definition: bfi.c:178

AVFrame

This structure describes decoded (raw) audio or video data.

Definition: frame.h:317

internal.h

AVPacket::data

uint8_t * data

Definition: packet.h:373

data

const char data[16]

Definition: mxf.c:143

BFIContext::pal

uint32_t pal[256]

Definition: bfi.c:37

bfi_decode_frame

static int bfi_decode_frame(AVCodecContext *avctx, void *data, int *got_frame, AVPacket *avpkt)

Definition: bfi.c:50

init

static int init

Definition: av_tx.c:47

bytestream2_skip

static av_always_inline void bytestream2_skip(GetByteContext *g, unsigned int size)

Definition: bytestream.h:168

#define U(x)

Definition: vp56_arith.h:37

AV_LOG_ERROR

#define AV_LOG_ERROR

Something went wrong and cannot losslessly be recovered.

Definition: log.h:180

av_cold

#define av_cold

Definition: attributes.h:90

decode

static void decode(AVCodecContext *dec_ctx, AVPacket *pkt, AVFrame *frame, FILE *outfile)

Definition: decode_audio.c:71

AVCodecContext::extradata_size

int extradata_size

Definition: avcodec.h:485

BFIContext

Definition: bfi.c:34

const char * g

Definition: vf_curves.c:117

AV_PICTURE_TYPE_I

@ AV_PICTURE_TYPE_I

Intra.

Definition: avutil.h:274

src

#define src

Definition: vp8dsp.c:255

bytestream2_get_buffer

static av_always_inline unsigned int bytestream2_get_buffer(GetByteContext *g, uint8_t *dst, unsigned int size)

Definition: bytestream.h:267

bytestream2_get_bytes_left

static av_always_inline int bytestream2_get_bytes_left(GetByteContext *g)

Definition: bytestream.h:158

for

for(j=16;j >0;--j)

Definition: h264pred_template.c:469

BFIContext::avctx

AVCodecContext * avctx

Definition: bfi.c:35

ff_get_buffer

int ff_get_buffer(AVCodecContext *avctx, AVFrame *frame, int flags)

Get a buffer for a frame.

Definition: decode.c:1652

AV_CODEC_CAP_DR1

#define AV_CODEC_CAP_DR1

Codec uses get_buffer() or get_encode_buffer() for allocating buffers and supports custom allocators.

Definition: codec.h:52

AVPacket::size

int size

Definition: packet.h:374

NULL_IF_CONFIG_SMALL

#define NULL_IF_CONFIG_SMALL(x)

Return NULL if CONFIG_SMALL is true, otherwise the argument without modification.

Definition: internal.h:117

bfi_decode_init

static av_cold int bfi_decode_init(AVCodecContext *avctx)

Definition: bfi.c:40

height

#define height

BFIContext::dst

uint8_t * dst

Definition: bfi.c:36

offset

it s the only field you need to keep assuming you have a context There is some magic you don t need to care about around this just let it vf offset

Definition: writing_filters.txt:86

#define i(width, name, range_min, range_max)

Definition: cbs_h2645.c:271

code

and forward the test the status of outputs and forward it to the corresponding return FFERROR_NOT_READY If the filters stores internally one or a few frame for some it can consider them to be part of the FIFO and delay acknowledging a status change accordingly Example code

Definition: filter_design.txt:178

AVCodecContext::extradata

uint8_t * extradata

some codecs need / can use extradata like Huffman tables.

Definition: avcodec.h:484

common.h

av_mallocz

void * av_mallocz(size_t size)

Allocate a memory block with alignment suitable for all memory accesses (including vectors if availab...

Definition: mem.c:263

AVCodec::name

const char * name

Name of the codec implementation.

Definition: codec.h:209

AVCodecContext::height

int height

Definition: avcodec.h:556

AVCodecContext::pix_fmt

enum AVPixelFormat pix_fmt

Pixel format, see AV_PIX_FMT_xxx.

Definition: avcodec.h:593

avcodec.h

AV_PIX_FMT_PAL8

@ AV_PIX_FMT_PAL8

8 bits with AV_PIX_FMT_RGB32 palette

Definition: pixfmt.h:77

av_uninit

#define av_uninit(x)

Definition: attributes.h:154

ret

Definition: filter_design.txt:187

frame

these buffered frames must be flushed immediately if a new input produces new the filter must not call request_frame to get more It must just process the frame or queue it The task of requesting more frames is left to the filter s request_frame method or the application If a filter has several the filter must be ready for frames arriving randomly on any input any filter with several inputs will most likely require some kind of queuing mechanism It is perfectly acceptable to have a limited queue and to drop frames when the inputs are too unbalanced request_frame For filters that do not use the this method is called when a frame is wanted on an output For a it should directly call filter_frame on the corresponding output For a if there are queued frames already one of these frames should be pushed If the filter should request a frame on one of its repeatedly until at least one frame has been pushed Return or at least make progress towards producing a frame

Definition: filter_design.txt:264

AVCodecContext

main external API structure.

Definition: avcodec.h:383

AV_CODEC_ID_BFI

@ AV_CODEC_ID_BFI

Definition: codec_id.h:167

frame_end

static void frame_end(MpegEncContext *s)

Definition: mpegvideo_enc.c:1583

shift

static int shift(int a, int b)