FFmpeg
bfi.c
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1 /*
2  * Brute Force & Ignorance (BFI) video decoder
3  * Copyright (c) 2008 Sisir Koppaka
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  */
21 
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  */
28 
29 #include "libavutil/common.h"
30 #include "avcodec.h"
31 #include "bytestream.h"
32 #include "internal.h"
33 
34 typedef struct BFIContext {
36  uint8_t *dst;
37  uint32_t pal[256];
38 } BFIContext;
39 
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 }
49 
50 static int bfi_decode_frame(AVCodecContext *avctx, void *data,
51  int *got_frame, AVPacket *avpkt)
52 {
53  AVFrame *frame = data;
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;
62 
63  if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
64  return ret;
65 
66  bytestream2_init(&g, avpkt->data, buf_size);
67 
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  }
94 
95  bytestream2_skip(&g, 4); // Unpacked size, not required.
96 
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 
172 {
173  BFIContext *bfi = avctx->priv_data;
174  av_freep(&bfi->dst);
175  return 0;
176 }
177 
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),
185  .close = bfi_decode_close,
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
init
static av_cold int init(AVCodecContext *avctx)
Definition: avrndec.c:31
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:303
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
bytestream2_skip
static av_always_inline void bytestream2_skip(GetByteContext *g, unsigned int size)
Definition: bytestream.h:168
U
#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
g
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
i
int i
Definition: input.c:406
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
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:1582
shift
static int shift(int a, int b)
Definition: sonic.c:83
AV_PICTURE_TYPE_P
@ AV_PICTURE_TYPE_P
Predicted.
Definition: avutil.h:275
AVMEDIA_TYPE_VIDEO
@ AVMEDIA_TYPE_VIDEO
Definition: avutil.h:201
AVCodecContext::frame_number
int frame_number
Frame counter, set by libavcodec.
Definition: avcodec.h:1023
AVPacket
This structure stores compressed data.
Definition: packet.h:350
AVCodecContext::priv_data
void * priv_data
Definition: avcodec.h:410
av_freep
#define av_freep(p)
Definition: tableprint_vlc.h:35
AVCodecContext::width
int width
picture width / height.
Definition: avcodec.h:556
bytestream.h
bytestream2_init
static av_always_inline void bytestream2_init(GetByteContext *g, const uint8_t *buf, int buf_size)
Definition: bytestream.h:137
av_log
#define av_log(a,...)
Definition: tableprint_vlc.h:28
AVERROR_INVALIDDATA
#define AVERROR_INVALIDDATA
Invalid data found when processing input.
Definition: error.h:61