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/mem.h"

30 #include "avcodec.h"

31 #include "bytestream.h"

32 #include "codec_internal.h"

33 #include "decode.h"

35 typedef struct BFIContext {

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, AVFrame *frame,

51 int *got_frame, AVPacket *avpkt)

52 {

53 GetByteContext g;

54 int buf_size = avpkt->size;

55 BFIContext *bfi = avctx->priv_data;

56 uint8_t *dst = bfi->dst;

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

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

59 uint32_t *pal;

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

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

63 return ret;

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

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

68 if (!avctx->frame_num) {

69 frame->pict_type = AV_PICTURE_TYPE_I;

70 frame->flags |= AV_FRAME_FLAG_KEY;

71 /* Setting the palette */

72 if (avctx->extradata_size > 768) {

73 av_log(avctx, AV_LOG_ERROR, "Palette is too large.\n");

74 return AVERROR_INVALIDDATA;

75 }

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

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

78 int shift = 16;

79 *pal = 0xFFU << 24;

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

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

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

83 pal++;

84 }

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

86 } else {

87 frame->pict_type = AV_PICTURE_TYPE_P;

88 frame->flags &= ~AV_FRAME_FLAG_KEY;

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

90 }

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

94 while (dst != frame_end) {

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

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

97 unsigned int code = byte >> 6;

98 unsigned int length = byte & ~0xC0;

100 if (!bytestream2_get_bytes_left(&g)) {

101 av_log(avctx, AV_LOG_ERROR,

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

103 return AVERROR_INVALIDDATA;

104 }

105

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

107 if (length == 0) {

108 if (code == 1) {

109 length = bytestream2_get_byte(&g);

110 offset = bytestream2_get_le16(&g);

111 } else {

112 length = bytestream2_get_le16(&g);

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

114 break;

115 }

116 } else {

117 if (code == 1)

118 offset = bytestream2_get_byte(&g);

119 }

120

121 /* Do boundary check */

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

123 break;

124

125 switch (code) {

126 case 0: // normal chain

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

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

129 return AVERROR_INVALIDDATA;

130 }

131 bytestream2_get_buffer(&g, dst, length);

132 dst += length;

133 break;

134 case 1: // back chain

135 dst_offset = dst - offset;

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

137 if (dst_offset < bfi->dst)

138 break;

139 while (length--)

140 *dst++ = *dst_offset++;

141 break;

142 case 2: // skip chain

143 dst += length;

144 break;

145 case 3: // fill chain

146 colour1 = bytestream2_get_byte(&g);

147 colour2 = bytestream2_get_byte(&g);

148 while (length--) {

149 *dst++ = colour1;

150 *dst++ = colour2;

151 }

152 break;

153 }

154 }

155

156 src = bfi->dst;

157 dst = frame->data[0];

158 while (height--) {

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

160 src += avctx->width;

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

162 }

163 *got_frame = 1;

164

165 return buf_size;

166 }

167

168 static av_cold int bfi_decode_close(AVCodecContext *avctx)

169 {

170 BFIContext *bfi = avctx->priv_data;

171 av_freep(&bfi->dst);

172 return 0;

173 }

174

175 const FFCodec ff_bfi_decoder = {

176 .p.name = "bfi",

177 CODEC_LONG_NAME("Brute Force & Ignorance"),

178 .p.type = AVMEDIA_TYPE_VIDEO,

179 .p.id = AV_CODEC_ID_BFI,

180 .priv_data_size = sizeof(BFIContext),

181 .init = bfi_decode_init,

182 .close = bfi_decode_close,

183 FF_CODEC_DECODE_CB(bfi_decode_frame),

184 .p.capabilities = AV_CODEC_CAP_DR1,

185 };

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

bytestream2_get_bytes_left

static av_always_inline int bytestream2_get_bytes_left(const GetByteContext *g)

Definition: bytestream.h:158

GetByteContext

Definition: bytestream.h:33

bfi_decode_close

static av_cold int bfi_decode_close(AVCodecContext *avctx)

Definition: bfi.c:168

AVFrame

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

Definition: frame.h:427

AVPacket::data

uint8_t * data

Definition: packet.h:588

FFCodec

Definition: codec_internal.h:127

BFIContext::pal

uint32_t pal[256]

Definition: bfi.c:37

static av_cold void close(AVCodecParserContext *s)

Definition: apv_parser.c:136

bytestream2_skip

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

Definition: bytestream.h:168

FFCodec::p

AVCodec p

The public AVCodec.

Definition: codec_internal.h:131

frame_end

static int64_t frame_end(const SyncQueue *sq, SyncQueueFrame frame, int nb_samples)

Compute the end timestamp of a frame.

Definition: sync_queue.c:118

AV_LOG_ERROR

#define AV_LOG_ERROR

Something went wrong and cannot losslessly be recovered.

Definition: log.h:210

av_cold

#define av_cold

Definition: attributes.h:106

AV_FRAME_FLAG_KEY

#define AV_FRAME_FLAG_KEY

A flag to mark frames that are keyframes.

Definition: frame.h:642

AVCodecContext::extradata_size

int extradata_size

Definition: avcodec.h:515

BFIContext

Definition: bfi.c:35

FF_CODEC_DECODE_CB

#define FF_CODEC_DECODE_CB(func)

Definition: codec_internal.h:347

const char * g

Definition: vf_curves.c:128

decode.h

CODEC_LONG_NAME

#define CODEC_LONG_NAME(str)

Definition: codec_internal.h:332

ff_bfi_decoder

const FFCodec ff_bfi_decoder

Definition: bfi.c:175

AV_PICTURE_TYPE_I

@ AV_PICTURE_TYPE_I

Intra.

Definition: avutil.h:278

bytestream2_get_buffer

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

Definition: bytestream.h:267

ff_get_buffer

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

Get a buffer for a frame.

Definition: decode.c:1728

init

int(* init)(AVBSFContext *ctx)

Definition: dts2pts.c:550

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:589

height

#define height

Definition: dsp.h:89

codec_internal.h

shift

static int shift(int a, int b)

Definition: bonk.c:261

dst

uint8_t ptrdiff_t const uint8_t ptrdiff_t int intptr_t intptr_t int int16_t * dst

Definition: dsp.h:87

for

for(k=2;k<=8;++k)

Definition: h264pred_template.c:424

bfi_decode_init

static av_cold int bfi_decode_init(AVCodecContext *avctx)

Definition: bfi.c:40

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:256

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

Out-of-band global headers that may be used by some codecs.

Definition: avcodec.h:514

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:256

AVCodec::name

const char * name

Name of the codec implementation.

Definition: codec.h:179

AVCodecContext::height

int height

Definition: avcodec.h:592

AVCodecContext::pix_fmt

enum AVPixelFormat pix_fmt

Pixel format, see AV_PIX_FMT_xxx.

Definition: avcodec.h:631

avcodec.h

AV_PIX_FMT_PAL8

@ AV_PIX_FMT_PAL8

8 bits with AV_PIX_FMT_RGB32 palette

Definition: pixfmt.h:84

AVCodecContext::frame_num

int64_t frame_num

Frame counter, set by libavcodec.

Definition: avcodec.h:1878

av_uninit

#define av_uninit(x)

Definition: attributes.h:174

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:265

#define U(x)

Definition: vpx_arith.h:37

AVCodecContext

main external API structure.

Definition: avcodec.h:431

AV_CODEC_ID_BFI

@ AV_CODEC_ID_BFI

Definition: codec_id.h:169

AV_PICTURE_TYPE_P

@ AV_PICTURE_TYPE_P

Predicted.