FFmpeg
vble.c
Go to the documentation of this file.
1 /*
2  * VBLE Decoder
3  * Copyright (c) 2011 Derek Buitenhuis
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  * VBLE Decoder
25  */
26 
27 #include "libavutil/imgutils.h"
28 
29 #define BITSTREAM_READER_LE
30 #include "avcodec.h"
31 #include "get_bits.h"
32 #include "internal.h"
33 #include "lossless_videodsp.h"
34 #include "mathops.h"
35 #include "thread.h"
36 
37 typedef struct VBLEContext {
40 
41  int size;
42  uint8_t *val; ///< This array first holds the lengths of vlc symbols and then their value.
43 } VBLEContext;
44 
46 {
47  int i;
48  int allbits = 0;
49  static const uint8_t LUT[256] = {
50  8,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,4,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,
51  5,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,4,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,
52  6,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,4,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,
53  5,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,4,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,
54  7,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,4,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,
55  5,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,4,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,
56  6,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,4,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,
57  5,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,4,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,
58  };
59 
60  /* Read all the lengths in first */
61  for (i = 0; i < ctx->size; i++) {
62  /* At most we need to read 9 bits total to get indices up to 8 */
63  int val = show_bits(gb, 8);
64 
65  // read reverse unary
66  if (val) {
67  val = LUT[val];
68  skip_bits(gb, val + 1);
69  ctx->val[i] = val;
70  } else {
71  skip_bits(gb, 8);
72  if (!get_bits1(gb))
73  return -1;
74  ctx->val[i] = 8;
75  }
76  allbits += ctx->val[i];
77  }
78 
79  /* Check we have enough bits left */
80  if (get_bits_left(gb) < allbits)
81  return -1;
82  return 0;
83 }
84 
86  GetBitContext *gb, int plane,
87  int offset, int width, int height)
88 {
89  uint8_t *dst = pic->data[plane];
90  uint8_t *val = ctx->val + offset;
91  int stride = pic->linesize[plane];
92  int i, j, left, left_top;
93 
94  for (i = 0; i < height; i++) {
95  for (j = 0; j < width; j++) {
96  /* get_bits can't take a length of 0 */
97  if (val[j]) {
98  int v = (1 << val[j]) + get_bits(gb, val[j]) - 1;
99  val[j] = (v >> 1) ^ -(v & 1);
100  }
101  }
102  if (i) {
103  left = 0;
104  left_top = dst[-stride];
105  ctx->llviddsp.add_median_pred(dst, dst - stride, val,
106  width, &left, &left_top);
107  } else {
108  dst[0] = val[0];
109  for (j = 1; j < width; j++)
110  dst[j] = val[j] + dst[j - 1];
111  }
112  dst += stride;
113  val += width;
114  }
115 }
116 
117 static int vble_decode_frame(AVCodecContext *avctx, void *data, int *got_frame,
118  AVPacket *avpkt)
119 {
120  VBLEContext *ctx = avctx->priv_data;
121  AVFrame *pic = data;
122  GetBitContext gb;
123  const uint8_t *src = avpkt->data;
124  int version;
125  int offset = 0;
126  int width_uv = avctx->width / 2, height_uv = avctx->height / 2;
127  int ret;
128  ThreadFrame frame = { .f = data };
129 
130  if (avpkt->size < 4 || avpkt->size - 4 > INT_MAX/8) {
131  av_log(avctx, AV_LOG_ERROR, "Invalid packet size\n");
132  return AVERROR_INVALIDDATA;
133  }
134 
135  /* Allocate buffer */
136  if ((ret = ff_thread_get_buffer(avctx, &frame, 0)) < 0)
137  return ret;
138 
139  /* Set flags */
140  pic->key_frame = 1;
142 
143  /* Version should always be 1 */
144  version = AV_RL32(src);
145 
146  if (version != 1)
147  av_log(avctx, AV_LOG_WARNING, "Unsupported VBLE Version: %d\n", version);
148 
149  init_get_bits(&gb, src + 4, (avpkt->size - 4) * 8);
150 
151  /* Unpack */
152  if (vble_unpack(ctx, &gb) < 0) {
153  av_log(avctx, AV_LOG_ERROR, "Invalid Code\n");
154  return AVERROR_INVALIDDATA;
155  }
156 
157  /* Restore planes. Should be almost identical to Huffyuv's. */
158  vble_restore_plane(ctx, pic, &gb, 0, offset, avctx->width, avctx->height);
159 
160  /* Chroma */
161  if (!(ctx->avctx->flags & AV_CODEC_FLAG_GRAY)) {
162  offset += avctx->width * avctx->height;
163  vble_restore_plane(ctx, pic, &gb, 1, offset, width_uv, height_uv);
164 
165  offset += width_uv * height_uv;
166  vble_restore_plane(ctx, pic, &gb, 2, offset, width_uv, height_uv);
167  }
168 
169  *got_frame = 1;
170 
171  return avpkt->size;
172 }
173 
175 {
176  VBLEContext *ctx = avctx->priv_data;
177  av_freep(&ctx->val);
178 
179  return 0;
180 }
181 
183 {
184  VBLEContext *ctx = avctx->priv_data;
185 
186  /* Stash for later use */
187  ctx->avctx = avctx;
188  ff_llviddsp_init(&ctx->llviddsp);
189 
190  avctx->pix_fmt = AV_PIX_FMT_YUV420P;
191  avctx->bits_per_raw_sample = 8;
192 
193  ctx->size = av_image_get_buffer_size(avctx->pix_fmt,
194  avctx->width, avctx->height, 1);
195 
196  ctx->val = av_malloc_array(ctx->size, sizeof(*ctx->val));
197 
198  if (!ctx->val) {
199  av_log(avctx, AV_LOG_ERROR, "Could not allocate values buffer.\n");
200  return AVERROR(ENOMEM);
201  }
202 
203  return 0;
204 }
205 
207  .name = "vble",
208  .long_name = NULL_IF_CONFIG_SMALL("VBLE Lossless Codec"),
209  .type = AVMEDIA_TYPE_VIDEO,
210  .id = AV_CODEC_ID_VBLE,
211  .priv_data_size = sizeof(VBLEContext),
213  .close = vble_decode_close,
216  .caps_internal = FF_CODEC_CAP_INIT_THREADSAFE,
217 };
AVCodec
AVCodec.
Definition: codec.h:197
stride
int stride
Definition: mace.c:144
AV_LOG_WARNING
#define AV_LOG_WARNING
Something somehow does not look correct.
Definition: log.h:186
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
get_bits_left
static int get_bits_left(GetBitContext *gb)
Definition: get_bits.h:850
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
vble_decode_close
static av_cold int vble_decode_close(AVCodecContext *avctx)
Definition: vble.c:174
VBLEContext::llviddsp
LLVidDSPContext llviddsp
Definition: vble.c:39
vble_decode_init
static av_cold int vble_decode_init(AVCodecContext *avctx)
Definition: vble.c:182
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
VBLEContext
Definition: vble.c:37
init_get_bits
static int init_get_bits(GetBitContext *s, const uint8_t *buffer, int bit_size)
Initialize GetBitContext.
Definition: get_bits.h:660
thread.h
AVFrame::data
uint8_t * data[AV_NUM_DATA_POINTERS]
pointer to the picture/channel planes.
Definition: frame.h:317
skip_bits
static void skip_bits(GetBitContext *s, int n)
Definition: get_bits.h:468
get_bits
static unsigned int get_bits(GetBitContext *s, int n)
Read 1-25 bits.
Definition: get_bits.h:380
GetBitContext
Definition: get_bits.h:62
ff_thread_get_buffer
the pkt_dts and pkt_pts fields in AVFrame will work as usual Restrictions on codec whose streams don t reset across will not work because their bitstreams cannot be decoded in parallel *The contents of buffers must not be read before as well as code calling up to before the decode process starts Call have so the codec calls ff_thread_report set FF_CODEC_CAP_ALLOCATE_PROGRESS in AVCodec caps_internal and use ff_thread_get_buffer() to allocate frames. The frames must then be freed with ff_thread_release_buffer(). Otherwise decode directly into the user-supplied frames. Call ff_thread_report_progress() after some part of the current picture has decoded. A good place to put this is where draw_horiz_band() is called - add this if it isn 't called anywhere
vble_restore_plane
static void vble_restore_plane(VBLEContext *ctx, AVFrame *pic, GetBitContext *gb, int plane, int offset, int width, int height)
Definition: vble.c:85
AVFrame::key_frame
int key_frame
1 -> keyframe, 0-> not
Definition: frame.h:381
val
static double val(void *priv, double ch)
Definition: aeval.c:75
LLVidDSPContext
Definition: lossless_videodsp.h:28
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
width
#define width
AVFormatContext::flags
int flags
Flags modifying the (de)muxer behaviour.
Definition: avformat.h:1225
AVCodecContext::bits_per_raw_sample
int bits_per_raw_sample
Bits per sample/pixel of internal libavcodec pixel/sample format.
Definition: avcodec.h:1421
ctx
AVFormatContext * ctx
Definition: movenc.c:48
get_bits.h
AV_PIX_FMT_YUV420P
@ AV_PIX_FMT_YUV420P
planar YUV 4:2:0, 12bpp, (1 Cr & Cb sample per 2x2 Y samples)
Definition: pixfmt.h:66
AV_CODEC_CAP_FRAME_THREADS
#define AV_CODEC_CAP_FRAME_THREADS
Codec supports frame-level multithreading.
Definition: codec.h:108
VBLEContext::size
int size
Definition: vble.c:41
AV_PICTURE_TYPE_I
@ AV_PICTURE_TYPE_I
Intra.
Definition: avutil.h:274
get_bits1
static unsigned int get_bits1(GetBitContext *s)
Definition: get_bits.h:499
src
#define src
Definition: vp8dsp.c:255
mathops.h
VBLEContext::avctx
AVCodecContext * avctx
Definition: vble.c:38
AVFrame::pict_type
enum AVPictureType pict_type
Picture type of the frame.
Definition: frame.h:386
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
AV_CODEC_FLAG_GRAY
#define AV_CODEC_FLAG_GRAY
Only decode/encode grayscale.
Definition: avcodec.h:243
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:116
VBLEContext::val
uint8_t * val
This array first holds the lengths of vlc symbols and then their value.
Definition: vble.c:42
height
#define height
av_image_get_buffer_size
int av_image_get_buffer_size(enum AVPixelFormat pix_fmt, int width, int height, int align)
Return the size in bytes of the amount of data required to store an image with the given parameters.
Definition: imgutils.c:466
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
version
version
Definition: libkvazaar.c:307
i
int i
Definition: input.c:406
show_bits
static unsigned int show_bits(GetBitContext *s, int n)
Show 1-25 bits.
Definition: get_bits.h:447
av_malloc_array
#define av_malloc_array(a, b)
Definition: tableprint_vlc.h:32
AVCodec::name
const char * name
Name of the codec implementation.
Definition: codec.h:204
AVCodecContext::height
int height
Definition: avcodec.h:552
AVCodecContext::pix_fmt
enum AVPixelFormat pix_fmt
Pixel format, see AV_PIX_FMT_xxx.
Definition: avcodec.h:589
avcodec.h
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
left
Tag MUST be and< 10hcoeff half pel interpolation filter coefficients, hcoeff[0] are the 2 middle coefficients[1] are the next outer ones and so on, resulting in a filter like:...eff[2], hcoeff[1], hcoeff[0], hcoeff[0], hcoeff[1], hcoeff[2] ... the sign of the coefficients is not explicitly stored but alternates after each coeff and coeff[0] is positive, so ...,+,-,+,-,+,+,-,+,-,+,... hcoeff[0] is not explicitly stored but found by subtracting the sum of all stored coefficients with signs from 32 hcoeff[0]=32 - hcoeff[1] - hcoeff[2] - ... a good choice for hcoeff and htaps is htaps=6 hcoeff={40,-10, 2} an alternative which requires more computations at both encoder and decoder side and may or may not be better is htaps=8 hcoeff={42,-14, 6,-2}ref_frames minimum of the number of available reference frames and max_ref_frames for example the first frame after a key frame always has ref_frames=1spatial_decomposition_type wavelet type 0 is a 9/7 symmetric compact integer wavelet 1 is a 5/3 symmetric compact integer wavelet others are reserved stored as delta from last, last is reset to 0 if always_reset||keyframeqlog quality(logarithmic quantizer scale) stored as delta from last, last is reset to 0 if always_reset||keyframemv_scale stored as delta from last, last is reset to 0 if always_reset||keyframe FIXME check that everything works fine if this changes between framesqbias dequantization bias stored as delta from last, last is reset to 0 if always_reset||keyframeblock_max_depth maximum depth of the block tree stored as delta from last, last is reset to 0 if always_reset||keyframequant_table quantization tableHighlevel bitstream structure:==============================--------------------------------------------|Header|--------------------------------------------|------------------------------------|||Block0||||split?||||yes no||||......... intra?||||:Block01 :yes no||||:Block02 :....... ..........||||:Block03 ::y DC ::ref index:||||:Block04 ::cb DC ::motion x :||||......... :cr DC ::motion y :||||....... ..........|||------------------------------------||------------------------------------|||Block1|||...|--------------------------------------------|------------ ------------ ------------|||Y subbands||Cb subbands||Cr subbands||||--- ---||--- ---||--- ---|||||LL0||HL0||||LL0||HL0||||LL0||HL0|||||--- ---||--- ---||--- ---||||--- ---||--- ---||--- ---|||||LH0||HH0||||LH0||HH0||||LH0||HH0|||||--- ---||--- ---||--- ---||||--- ---||--- ---||--- ---|||||HL1||LH1||||HL1||LH1||||HL1||LH1|||||--- ---||--- ---||--- ---||||--- ---||--- ---||--- ---|||||HH1||HL2||||HH1||HL2||||HH1||HL2|||||...||...||...|||------------ ------------ ------------|--------------------------------------------Decoding process:=================------------|||Subbands|------------||||------------|Intra DC||||LL0 subband prediction ------------|\ Dequantization ------------------- \||Reference frames|\ IDWT|------- -------|Motion \|||Frame 0||Frame 1||Compensation . OBMC v -------|------- -------|--------------. \------> Frame n output Frame Frame<----------------------------------/|...|------------------- Range Coder:============Binary Range Coder:------------------- The implemented range coder is an adapted version based upon "Range encoding: an algorithm for removing redundancy from a digitised message." by G. N. N. Martin. The symbols encoded by the Snow range coder are bits(0|1). The associated probabilities are not fix but change depending on the symbol mix seen so far. bit seen|new state ---------+----------------------------------------------- 0|256 - state_transition_table[256 - old_state];1|state_transition_table[old_state];state_transition_table={ 0, 0, 0, 0, 0, 0, 0, 0, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 94, 95, 96, 97, 98, 99, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112, 113, 114, 114, 115, 116, 117, 118, 119, 120, 121, 122, 123, 124, 125, 126, 127, 128, 129, 130, 131, 132, 133, 133, 134, 135, 136, 137, 138, 139, 140, 141, 142, 143, 144, 145, 146, 147, 148, 149, 150, 151, 152, 152, 153, 154, 155, 156, 157, 158, 159, 160, 161, 162, 163, 164, 165, 166, 167, 168, 169, 170, 171, 171, 172, 173, 174, 175, 176, 177, 178, 179, 180, 181, 182, 183, 184, 185, 186, 187, 188, 189, 190, 190, 191, 192, 194, 194, 195, 196, 197, 198, 199, 200, 201, 202, 202, 204, 205, 206, 207, 208, 209, 209, 210, 211, 212, 213, 215, 215, 216, 217, 218, 219, 220, 220, 222, 223, 224, 225, 226, 227, 227, 229, 229, 230, 231, 232, 234, 234, 235, 236, 237, 238, 239, 240, 241, 242, 243, 244, 245, 246, 247, 248, 248, 0, 0, 0, 0, 0, 0, 0};FIXME Range Coding of integers:------------------------- FIXME Neighboring Blocks:===================left and top are set to the respective blocks unless they are outside of the image in which case they are set to the Null block top-left is set to the top left block unless it is outside of the image in which case it is set to the left block if this block has no larger parent block or it is at the left side of its parent block and the top right block is not outside of the image then the top right block is used for top-right else the top-left block is used Null block y, cb, cr are 128 level, ref, mx and my are 0 Motion Vector Prediction:=========================1. the motion vectors of all the neighboring blocks are scaled to compensate for the difference of reference frames scaled_mv=(mv *(256 *(current_reference+1)/(mv.reference+1))+128)> the median of the scaled left
Definition: snow.txt:386
AV_RL32
uint64_t_TMPL AV_WL64 unsigned int_TMPL AV_RL32
Definition: bytestream.h:92
ff_llviddsp_init
void ff_llviddsp_init(LLVidDSPContext *c)
Definition: lossless_videodsp.c:113
AVCodecContext
main external API structure.
Definition: avcodec.h:379
ThreadFrame
Definition: thread.h:34
vble_decode_frame
static int vble_decode_frame(AVCodecContext *avctx, void *data, int *got_frame, AVPacket *avpkt)
Definition: vble.c:117
AVMEDIA_TYPE_VIDEO
@ AVMEDIA_TYPE_VIDEO
Definition: avutil.h:201
AV_CODEC_ID_VBLE
@ AV_CODEC_ID_VBLE
Definition: codec_id.h:205
lossless_videodsp.h
AVCodecContext::priv_data
void * priv_data
Definition: avcodec.h:406
AVPacket
This structure stores compressed data.
Definition: packet.h:350
av_freep
#define av_freep(p)
Definition: tableprint_vlc.h:35
AVCodecContext::width
int width
picture width / height.
Definition: avcodec.h:552
imgutils.h
AVFrame::linesize
int linesize[AV_NUM_DATA_POINTERS]
For video, size in bytes of each picture line.
Definition: frame.h:334
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:59
ff_vble_decoder
const AVCodec ff_vble_decoder
Definition: vble.c:206
vble_unpack
static int vble_unpack(VBLEContext *ctx, GetBitContext *gb)
Definition: vble.c:45