FFmpeg
mdec.c
Go to the documentation of this file.
1 /*
2  * Sony PlayStation MDEC (Motion DECoder)
3  * Copyright (c) 2003 Michael Niedermayer
4  *
5  * based upon code from Sebastian Jedruszkiewicz <elf@frogger.rules.pl>
6  *
7  * This file is part of FFmpeg.
8  *
9  * FFmpeg is free software; you can redistribute it and/or
10  * modify it under the terms of the GNU Lesser General Public
11  * License as published by the Free Software Foundation; either
12  * version 2.1 of the License, or (at your option) any later version.
13  *
14  * FFmpeg is distributed in the hope that it will be useful,
15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
17  * Lesser General Public License for more details.
18  *
19  * You should have received a copy of the GNU Lesser General Public
20  * License along with FFmpeg; if not, write to the Free Software
21  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
22  */
23 
24 /**
25  * @file
26  * Sony PlayStation MDEC (Motion DECoder)
27  * This is very similar to intra-only MPEG-1.
28  */
29 
30 #include "avcodec.h"
31 #include "blockdsp.h"
32 #include "bswapdsp.h"
33 #include "idctdsp.h"
34 #include "mpeg12.h"
35 #include "thread.h"
36 
37 typedef struct MDECContext {
45  int version;
46  int qscale;
47  int last_dc[3];
48  int mb_width;
49  int mb_height;
50  int mb_x, mb_y;
51  DECLARE_ALIGNED(32, int16_t, block)[6][64];
52  DECLARE_ALIGNED(16, uint16_t, quant_matrix)[64];
54  unsigned int bitstream_buffer_size;
56 } MDECContext;
57 
58 //very similar to MPEG-1
59 static inline int mdec_decode_block_intra(MDECContext *a, int16_t *block, int n)
60 {
61  int level, diff, i, j, run;
62  int component;
63  RLTable *rl = &ff_rl_mpeg1;
65  const uint16_t *quant_matrix = a->quant_matrix;
66  const int qscale = a->qscale;
67 
68  /* DC coefficient */
69  if (a->version == 2) {
70  block[0] = 2 * get_sbits(&a->gb, 10) + 1024;
71  } else {
72  component = (n <= 3 ? 0 : n - 4 + 1);
73  diff = decode_dc(&a->gb, component);
74  if (diff >= 0xffff)
75  return AVERROR_INVALIDDATA;
76  a->last_dc[component] += diff;
77  block[0] = a->last_dc[component] * (1 << 3);
78  }
79 
80  i = 0;
81  {
82  OPEN_READER(re, &a->gb);
83  /* now quantify & encode AC coefficients */
84  for (;;) {
85  UPDATE_CACHE(re, &a->gb);
86  GET_RL_VLC(level, run, re, &a->gb, rl->rl_vlc[0], TEX_VLC_BITS, 2, 0);
87 
88  if (level == 127) {
89  break;
90  } else if (level != 0) {
91  i += run;
92  if (i > 63) {
94  "ac-tex damaged at %d %d\n", a->mb_x, a->mb_y);
95  return AVERROR_INVALIDDATA;
96  }
97  j = scantable[i];
98  level = (level * qscale * quant_matrix[j]) >> 3;
99  level = (level ^ SHOW_SBITS(re, &a->gb, 1)) - SHOW_SBITS(re, &a->gb, 1);
100  LAST_SKIP_BITS(re, &a->gb, 1);
101  } else {
102  /* escape */
103  run = SHOW_UBITS(re, &a->gb, 6)+1; LAST_SKIP_BITS(re, &a->gb, 6);
104  UPDATE_CACHE(re, &a->gb);
105  level = SHOW_SBITS(re, &a->gb, 10); SKIP_BITS(re, &a->gb, 10);
106  i += run;
107  if (i > 63) {
109  "ac-tex damaged at %d %d\n", a->mb_x, a->mb_y);
110  return AVERROR_INVALIDDATA;
111  }
112  j = scantable[i];
113  if (level < 0) {
114  level = -level;
115  level = (level * (unsigned)qscale * quant_matrix[j]) >> 3;
116  level = (level - 1) | 1;
117  level = -level;
118  } else {
119  level = (level * (unsigned)qscale * quant_matrix[j]) >> 3;
120  level = (level - 1) | 1;
121  }
122  }
123 
124  block[j] = level;
125  }
126  CLOSE_READER(re, &a->gb);
127  }
128  a->block_last_index[n] = i;
129  return 0;
130 }
131 
132 static inline int decode_mb(MDECContext *a, int16_t block[6][64])
133 {
134  int i, ret;
135  static const int block_index[6] = { 5, 4, 0, 1, 2, 3 };
136 
137  a->bdsp.clear_blocks(block[0]);
138 
139  for (i = 0; i < 6; i++) {
140  if ((ret = mdec_decode_block_intra(a, block[block_index[i]],
141  block_index[i])) < 0)
142  return ret;
143  if (get_bits_left(&a->gb) < 0)
144  return AVERROR_INVALIDDATA;
145  }
146  return 0;
147 }
148 
149 static inline void idct_put(MDECContext *a, AVFrame *frame, int mb_x, int mb_y)
150 {
151  int16_t (*block)[64] = a->block;
152  int linesize = frame->linesize[0];
153 
154  uint8_t *dest_y = frame->data[0] + (mb_y * 16* linesize ) + mb_x * 16;
155  uint8_t *dest_cb = frame->data[1] + (mb_y * 8 * frame->linesize[1]) + mb_x * 8;
156  uint8_t *dest_cr = frame->data[2] + (mb_y * 8 * frame->linesize[2]) + mb_x * 8;
157 
158  a->idsp.idct_put(dest_y, linesize, block[0]);
159  a->idsp.idct_put(dest_y + 8, linesize, block[1]);
160  a->idsp.idct_put(dest_y + 8 * linesize, linesize, block[2]);
161  a->idsp.idct_put(dest_y + 8 * linesize + 8, linesize, block[3]);
162 
163  if (!(a->avctx->flags & AV_CODEC_FLAG_GRAY)) {
164  a->idsp.idct_put(dest_cb, frame->linesize[1], block[4]);
165  a->idsp.idct_put(dest_cr, frame->linesize[2], block[5]);
166  }
167 }
168 
170  void *data, int *got_frame,
171  AVPacket *avpkt)
172 {
173  MDECContext * const a = avctx->priv_data;
174  const uint8_t *buf = avpkt->data;
175  int buf_size = avpkt->size;
176  ThreadFrame frame = { .f = data };
177  int ret;
178 
179  if ((ret = ff_thread_get_buffer(avctx, &frame, 0)) < 0)
180  return ret;
181  frame.f->pict_type = AV_PICTURE_TYPE_I;
182  frame.f->key_frame = 1;
183 
185  if (!a->bitstream_buffer)
186  return AVERROR(ENOMEM);
187  a->bbdsp.bswap16_buf((uint16_t *)a->bitstream_buffer, (uint16_t *)buf, (buf_size + 1) / 2);
188  if ((ret = init_get_bits8(&a->gb, a->bitstream_buffer, buf_size)) < 0)
189  return ret;
190 
191  /* skip over 4 preamble bytes in stream (typically 0xXX 0xXX 0x00 0x38) */
192  skip_bits(&a->gb, 32);
193 
194  a->qscale = get_bits(&a->gb, 16);
195  a->version = get_bits(&a->gb, 16);
196 
197  a->last_dc[0] = a->last_dc[1] = a->last_dc[2] = 128;
198 
199  for (a->mb_x = 0; a->mb_x < a->mb_width; a->mb_x++) {
200  for (a->mb_y = 0; a->mb_y < a->mb_height; a->mb_y++) {
201  if ((ret = decode_mb(a, a->block)) < 0)
202  return ret;
203 
204  idct_put(a, frame.f, a->mb_x, a->mb_y);
205  }
206  }
207 
208  *got_frame = 1;
209 
210  return (get_bits_count(&a->gb) + 31) / 32 * 4;
211 }
212 
214 {
215  MDECContext * const a = avctx->priv_data;
216  int i;
217 
218  a->mb_width = (avctx->coded_width + 15) / 16;
219  a->mb_height = (avctx->coded_height + 15) / 16;
220 
221  a->avctx = avctx;
222 
223  ff_blockdsp_init(&a->bdsp, avctx);
224  ff_bswapdsp_init(&a->bbdsp);
225  ff_idctdsp_init(&a->idsp, avctx);
229 
230  avctx->pix_fmt = AV_PIX_FMT_YUVJ420P;
231  avctx->color_range = AVCOL_RANGE_JPEG;
232 
233  /* init q matrix */
234  for (i = 0; i < 64; i++) {
235  int j = a->idsp.idct_permutation[i];
236 
238  }
239 
240  return 0;
241 }
242 
243 #if HAVE_THREADS
244 static av_cold int decode_init_thread_copy(AVCodecContext *avctx)
245 {
246  MDECContext * const a = avctx->priv_data;
247 
248  a->avctx = avctx;
249 
250  return 0;
251 }
252 #endif
253 
255 {
256  MDECContext * const a = avctx->priv_data;
257 
259  a->bitstream_buffer_size = 0;
260 
261  return 0;
262 }
263 
265  .name = "mdec",
266  .long_name = NULL_IF_CONFIG_SMALL("Sony PlayStation MDEC (Motion DECoder)"),
267  .type = AVMEDIA_TYPE_VIDEO,
268  .id = AV_CODEC_ID_MDEC,
269  .priv_data_size = sizeof(MDECContext),
270  .init = decode_init,
271  .close = decode_end,
272  .decode = decode_frame,
274  .init_thread_copy = ONLY_IF_THREADS_ENABLED(decode_init_thread_copy)
275 };
static int decode_mb(MDECContext *a, int16_t block[6][64])
Definition: mdec.c:132
AVCodecContext * avctx
Definition: mdec.c:38
#define AVERROR_INVALIDDATA
Invalid data found when processing input.
Definition: error.h:59
This structure describes decoded (raw) audio or video data.
Definition: frame.h:295
void(* bswap16_buf)(uint16_t *dst, const uint16_t *src, int len)
Definition: bswapdsp.h:26
ptrdiff_t const GLvoid * data
Definition: opengl_enc.c:100
int coded_width
Bitstream width / height, may be different from width/height e.g.
Definition: avcodec.h:1756
float re
Definition: fft.c:82
static unsigned int get_bits(GetBitContext *s, int n)
Read 1-25 bits.
Definition: get_bits.h:379
av_cold void ff_mpeg12_init_vlcs(void)
Definition: mpeg12.c:137
AVFrame * f
Definition: thread.h:35
static av_cold int init(AVCodecContext *avctx)
Definition: avrndec.c:35
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 add an init_thread_copy() which re-allocates them for other threads.Add AV_CODEC_CAP_FRAME_THREADS to the codec capabilities.There will be very little speed gain at this point but it should work.If there are inter-frame dependencies
ThreadFrame frame
Definition: mdec.c:42
int mb_x
Definition: mdec.c:50
enum AVColorRange color_range
MPEG vs JPEG YUV range.
Definition: avcodec.h:2203
Scantable.
Definition: idctdsp.h:31
int size
Definition: avcodec.h:1481
av_cold void ff_blockdsp_init(BlockDSPContext *c, AVCodecContext *avctx)
Definition: blockdsp.c:60
GetBitContext gb
Definition: mdec.c:43
The reader does not expect b to be semantically here and if the code is changed by maybe adding a a division or other the signedness will almost certainly be mistaken To avoid this confusion a new type was SUINT is the C unsigned type but it holds a signed int to use the same example SUINT a
Definition: undefined.txt:36
enum AVPixelFormat pix_fmt
Pixel format, see AV_PIX_FMT_xxx.
Definition: avcodec.h:1778
void av_fast_padded_malloc(void *ptr, unsigned int *size, size_t min_size)
Same behaviour av_fast_malloc but the buffer has additional AV_INPUT_BUFFER_PADDING_SIZE at the end w...
Definition: utils.c:70
uint8_t permutated[64]
Definition: idctdsp.h:33
uint8_t run
Definition: svq3.c:206
AVCodec.
Definition: avcodec.h:3492
RLTable.
Definition: rl.h:39
static int get_sbits(GetBitContext *s, int n)
Definition: get_bits.h:359
static void decode(AVCodecContext *dec_ctx, AVPacket *pkt, AVFrame *frame, FILE *outfile)
Definition: decode_audio.c:71
uint8_t
#define av_cold
Definition: attributes.h:82
Multithreading support functions.
static int decode_frame(AVCodecContext *avctx, void *data, int *got_frame, AVPacket *avpkt)
Definition: mdec.c:169
#define DECLARE_ALIGNED(n, t, v)
Declare a variable that is aligned in memory.
Definition: mem.h:112
uint8_t * data
Definition: avcodec.h:1480
int mb_width
Definition: mdec.c:48
static int get_bits_count(const GetBitContext *s)
Definition: get_bits.h:219
int block_last_index[6]
Definition: mdec.c:55
#define AV_CODEC_FLAG_GRAY
Only decode/encode grayscale.
Definition: avcodec.h:886
#define av_log(a,...)
static int get_bits_left(GetBitContext *gb)
Definition: get_bits.h:849
#define UPDATE_CACHE(name, gb)
Definition: get_bits.h:178
#define i(width, name, range_min, range_max)
Definition: cbs_h2645.c:259
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:176
int qscale
Definition: mdec.c:46
void(* clear_blocks)(int16_t *blocks)
Definition: blockdsp.h:37
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification. ...
Definition: internal.h:186
int flags
AV_CODEC_FLAG_*.
Definition: avcodec.h:1648
BswapDSPContext bbdsp
Definition: mdec.c:40
const char * name
Name of the codec implementation.
Definition: avcodec.h:3499
int16_t block[6][64]
Definition: mdec.c:51
#define CLOSE_READER(name, gb)
Definition: get_bits.h:149
static int decode_dc(GetBitContext *gb, int component)
Definition: mpeg12.h:41
#define AV_CODEC_CAP_FRAME_THREADS
Codec supports frame-level multithreading.
Definition: avcodec.h:1040
#define GET_RL_VLC(level, run, name, gb, table, bits,max_depth, need_update)
Definition: get_bits.h:738
#define SKIP_BITS(name, gb, num)
Definition: get_bits.h:193
#define ONLY_IF_THREADS_ENABLED(x)
Define a function with only the non-default version specified.
Definition: internal.h:225
enum AVPictureType pict_type
Picture type of the frame.
Definition: frame.h:378
planar YUV 4:2:0, 12bpp, full scale (JPEG), deprecated in favor of AV_PIX_FMT_YUV420P and setting col...
Definition: pixfmt.h:78
RLTable ff_rl_mpeg1
Definition: mpeg12data.c:166
int mb_height
Definition: mdec.c:49
unsigned int bitstream_buffer_size
Definition: mdec.c:54
#define LAST_SKIP_BITS(name, gb, num)
Definition: get_bits.h:199
int n
Definition: avisynth_c.h:760
uint8_t * bitstream_buffer
Definition: mdec.c:53
uint8_t idct_permutation[64]
IDCT input permutation.
Definition: idctdsp.h:96
void(* idct_put)(uint8_t *dest, ptrdiff_t line_size, int16_t *block)
block -> idct -> clip to unsigned 8 bit -> dest.
Definition: idctdsp.h:72
RL_VLC_ELEM * rl_vlc[32]
decoding only
Definition: rl.h:48
#define SHOW_UBITS(name, gb, num)
Definition: get_bits.h:211
the normal 2^n-1 "JPEG" YUV ranges
Definition: pixfmt.h:523
Libavcodec external API header.
int linesize[AV_NUM_DATA_POINTERS]
For video, size in bytes of each picture line.
Definition: frame.h:326
static int init_get_bits8(GetBitContext *s, const uint8_t *buffer, int byte_size)
Initialize GetBitContext.
Definition: get_bits.h:677
IDCTDSPContext idsp
Definition: mdec.c:41
int ff_thread_get_buffer(AVCodecContext *avctx, ThreadFrame *f, int flags)
Wrapper around get_buffer() for frame-multithreaded codecs.
ScanTable scantable
Definition: mdec.c:44
main external API structure.
Definition: avcodec.h:1568
#define OPEN_READER(name, gb)
Definition: get_bits.h:138
static av_cold int decode_end(AVCodecContext *avctx)
Definition: mdec.c:254
void * buf
Definition: avisynth_c.h:766
int coded_height
Definition: avcodec.h:1756
static void skip_bits(GetBitContext *s, int n)
Definition: get_bits.h:467
static int mdec_decode_block_intra(MDECContext *a, int16_t *block, int n)
Definition: mdec.c:59
const uint16_t ff_mpeg1_default_intra_matrix[256]
Definition: mpeg12data.c:30
const uint8_t ff_zigzag_direct[64]
Definition: mathtables.c:98
uint16_t quant_matrix[64]
Definition: mdec.c:52
uint8_t * data[AV_NUM_DATA_POINTERS]
pointer to the picture/channel planes.
Definition: frame.h:309
uint8_t level
Definition: svq3.c:207
BlockDSPContext bdsp
Definition: mdec.c:39
#define SHOW_SBITS(name, gb, num)
Definition: get_bits.h:212
#define TEX_VLC_BITS
Definition: dv.h:96
int mb_y
Definition: mdec.c:50
av_cold void ff_bswapdsp_init(BswapDSPContext *c)
Definition: bswapdsp.c:49
void * priv_data
Definition: avcodec.h:1595
static av_always_inline int diff(const uint32_t a, const uint32_t b)
av_cold void ff_init_scantable(uint8_t *permutation, ScanTable *st, const uint8_t *src_scantable)
Definition: idctdsp.c:29
av_cold void ff_idctdsp_init(IDCTDSPContext *c, AVCodecContext *avctx)
Definition: idctdsp.c:238
int key_frame
1 -> keyframe, 0-> not
Definition: frame.h:373
AVCodec ff_mdec_decoder
Definition: mdec.c:264
static void idct_put(MDECContext *a, AVFrame *frame, int mb_x, int mb_y)
Definition: mdec.c:149
#define av_freep(p)
static av_cold int decode_init(AVCodecContext *avctx)
Definition: mdec.c:213
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
This structure stores compressed data.
Definition: avcodec.h:1457
#define AV_CODEC_CAP_DR1
Codec uses get_buffer() for allocating buffers and supports custom allocators.
Definition: avcodec.h:984
int last_dc[3]
Definition: mdec.c:47
int version
Definition: mdec.c:45