source/jdmerge.c (LibJPEG)

Outline

#define JPEG_INTERNALS

#include "jinclude.h"

#include "jpeglib.h"

my_upsampler

my_upsample_ptr

#define SCALEBITS

#define ONE_HALF

#define FIX

build_ycc_rgb_table(j_decompress_ptr)

start_pass_merged_upsample(j_decompress_ptr)

merged_2v_upsample(j_decompress_ptr, JSAMPIMAGE, JDIMENSION *, JDIMENSION, JSAMPARRAY, JDIMENSION *, JDIMENSION)

merged_1v_upsample(j_decompress_ptr, JSAMPIMAGE, JDIMENSION *, JDIMENSION, JSAMPARRAY, JDIMENSION *, JDIMENSION)

h2v1_merged_upsample(j_decompress_ptr, JSAMPIMAGE, JDIMENSION, JSAMPARRAY)

h2v2_merged_upsample(j_decompress_ptr, JSAMPIMAGE, JDIMENSION, JSAMPARRAY)

jinit_merged_upsampler(j_decompress_ptr)

Files

SourceVuSTM32 Libraries and SamplesLibJPEGsource/jdmerge.c

100

101

102

103

104

105

106

107

108

109

110

111

112

113

114

115

116

117

118

119

120

121

122

123

124

125

126

127

128

129

130

131

132

133

134

135

136

137

138

139

140

141

142

143

144

145

146

147

148

149

150

151

152

153

154

155

156

157

158

159

160

161

162

163

164

165

166

167

168

169

170

171

172

173

174

175

176

177

178

179

180

181

182

183

184

185

186

187

188

189

190

191

192

193

194

195

196

197

198

199

200

201

202

203

204

205

206

207

208

209

210

211

212

213

214

215

216

217

218

219

220

221

222

223

224

225

226

227

228

229

230

231

232

233

234

235

236

237

238

239

240

241

242

243

244

245

246

247

248

249

250

251

252

253

254

255

256

257

258

259

260

261

262

263

264

265

266

267

268

269

270

271

272

273

274

275

276

277

278

279

280

281

282

283

284

285

286

287

288

289

290

291

292

293

294

295

296

297

298

299

300

301

302

303

304

305

306

307

308

309

310

311

312

313

314

315

316

317

318

319

320

321

322

323

324

325

326

327

328

329

330

331

332

333

334

335

336

337

338

339

340

341

342

343

344

345

346

347

348

349

350

351

352

353

354

355

356

357

358

359

360

361

362

363

364

365

366

367

368

369

370

371

372

373

374

375

376

377

378

379

380

381

382

383

384

385

386

387

388

389

390

391

392

393

394

395

396

397

398

399

400

/* * jdmerge.c * * Copyright (C) 1994-1996, Thomas G. Lane. * This file is part of the Independent JPEG Group's software. * For conditions of distribution and use, see the accompanying README file. * * This file contains code for merged upsampling/color conversion. * * This file combines functions from jdsample.c and jdcolor.c; * read those files first to understand what's going on. * * When the chroma components are to be upsampled by simple replication * (ie, box filtering), we can save some work in color conversion by * calculating all the output pixels corresponding to a pair of chroma * samples at one time. In the conversion equations * R = Y + K1 * Cr * G = Y + K2 * Cb + K3 * Cr * B = Y + K4 * Cb * only the Y term varies among the group of pixels corresponding to a pair * of chroma samples, so the rest of the terms can be calculated just once. * At typical sampling ratios, this eliminates half or three-quarters of the * multiplications needed for color conversion. * * This file currently provides implementations for the following cases: * YCbCr => RGB color conversion only. * Sampling ratios of 2h1v or 2h2v. * No scaling needed at upsample time. * Corner-aligned (non-CCIR601) sampling alignment. * Other special cases could be added, but in most applications these are * the only common cases. (For uncommon cases we fall back on the more * general code in jdsample.c and jdcolor.c.) */ #define JPEG_INTERNALS #include "jinclude.h" #include "jpeglib.h" #ifdef UPSAMPLE_MERGING_SUPPORTED /* Private subobject */ typedef struct { struct jpeg_upsampler pub; /* public fields */ /* Pointer to routine to do actual upsampling/conversion of one row group */ JMETHOD(void, upmethod, (j_decompress_ptr cinfo, JSAMPIMAGE input_buf, JDIMENSION in_row_group_ctr, JSAMPARRAY output_buf)); /* Private state for YCC->RGB conversion */ int * Cr_r_tab; /* => table for Cr to R conversion */ int * Cb_b_tab; /* => table for Cb to B conversion */ INT32 * Cr_g_tab; /* => table for Cr to G conversion */ INT32 * Cb_g_tab; /* => table for Cb to G conversion */ /* For 2:1 vertical sampling, we produce two output rows at a time. * We need a "spare" row buffer to hold the second output row if the * application provides just a one-row buffer; we also use the spare * to discard the dummy last row if the image height is odd. */ JSAMPROW spare_row; boolean spare_full; /* T if spare buffer is occupied */ JDIMENSION out_row_width; /* samples per output row */ JDIMENSION rows_to_go; /* counts rows remaining in image */ } my_upsampler; typedef my_upsampler * my_upsample_ptr; #define SCALEBITS 16 /* speediest right-shift on some machines */ #define ONE_HALF ((INT32) 1 << (SCALEBITS-1)) #define FIX(x) ((INT32) ((x) * (1L<<SCALEBITS) + 0.5)) /* * Initialize tables for YCC->RGB colorspace conversion. * This is taken directly from jdcolor.c; see that file for more info. */ LOCAL(void) build_ycc_rgb_table (j_decompress_ptr cinfo) { my_upsample_ptr upsample = (my_upsample_ptr) cinfo->upsample; int i; INT32 x; SHIFT_TEMPS upsample->Cr_r_tab = (int *) (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE, (MAXJSAMPLE+1) * SIZEOF(int)); upsample->Cb_b_tab = (int *) (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE, (MAXJSAMPLE+1) * SIZEOF(int)); upsample->Cr_g_tab = (INT32 *) (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE, (MAXJSAMPLE+1) * SIZEOF(INT32)); upsample->Cb_g_tab = (INT32 *) (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE, (MAXJSAMPLE+1) * SIZEOF(INT32)); for (i = 0, x = -CENTERJSAMPLE; i <= MAXJSAMPLE; i++, x++) { /* i is the actual input pixel value, in the range 0..MAXJSAMPLE */ /* The Cb or Cr value we are thinking of is x = i - CENTERJSAMPLE */ /* Cr=>R value is nearest int to 1.40200 * x */ upsample->Cr_r_tab[i] = (int) RIGHT_SHIFT(FIX(1.40200) * x + ONE_HALF, SCALEBITS); /* Cb=>B value is nearest int to 1.77200 * x */ upsample->Cb_b_tab[i] = (int) RIGHT_SHIFT(FIX(1.77200) * x + ONE_HALF, SCALEBITS); /* Cr=>G value is scaled-up -0.71414 * x */ upsample->Cr_g_tab[i] = (- FIX(0.71414)) * x; /* Cb=>G value is scaled-up -0.34414 * x */ /* We also add in ONE_HALF so that need not do it in inner loop */ upsample->Cb_g_tab[i] = (- FIX(0.34414)) * x + ONE_HALF; } } /* * Initialize for an upsampling pass. */ METHODDEF(void) start_pass_merged_upsample (j_decompress_ptr cinfo) { my_upsample_ptr upsample = (my_upsample_ptr) cinfo->upsample; /* Mark the spare buffer empty */ upsample->spare_full = FALSE; /* Initialize total-height counter for detecting bottom of image */ upsample->rows_to_go = cinfo->output_height; } /* * Control routine to do upsampling (and color conversion). * * The control routine just handles the row buffering considerations. */ METHODDEF(void) merged_2v_upsample (j_decompress_ptr cinfo, JSAMPIMAGE input_buf, JDIMENSION *in_row_group_ctr, JDIMENSION in_row_groups_avail, JSAMPARRAY output_buf, JDIMENSION *out_row_ctr, JDIMENSION out_rows_avail) /* 2:1 vertical sampling case: may need a spare row. */ { my_upsample_ptr upsample = (my_upsample_ptr) cinfo->upsample; JSAMPROW work_ptrs[2]; JDIMENSION num_rows; /* number of rows returned to caller */ if (upsample->spare_full) { /* If we have a spare row saved from a previous cycle, just return it. */ jcopy_sample_rows(& upsample->spare_row, 0, output_buf + *out_row_ctr, 0, 1, upsample->out_row_width); num_rows = 1; upsample->spare_full = FALSE; } else { /* Figure number of rows to return to caller. */ num_rows = 2; /* Not more than the distance to the end of the image. */ if (num_rows > upsample->rows_to_go) num_rows = upsample->rows_to_go; /* And not more than what the client can accept: */ out_rows_avail -= *out_row_ctr; if (num_rows > out_rows_avail) num_rows = out_rows_avail; /* Create output pointer array for upsampler. */ work_ptrs[0] = output_buf[*out_row_ctr]; if (num_rows > 1) { work_ptrs[1] = output_buf[*out_row_ctr + 1]; } else { work_ptrs[1] = upsample->spare_row; upsample->spare_full = TRUE; } /* Now do the upsampling. */ (*upsample->upmethod) (cinfo, input_buf, *in_row_group_ctr, work_ptrs); } /* Adjust counts */ *out_row_ctr += num_rows; upsample->rows_to_go -= num_rows; /* When the buffer is emptied, declare this input row group consumed */ if (! upsample->spare_full) (*in_row_group_ctr)++; } METHODDEF(void) merged_1v_upsample (j_decompress_ptr cinfo, JSAMPIMAGE input_buf, JDIMENSION *in_row_group_ctr, JDIMENSION in_row_groups_avail, JSAMPARRAY output_buf, JDIMENSION *out_row_ctr, JDIMENSION out_rows_avail) /* 1:1 vertical sampling case: much easier, never need a spare row. */ { my_upsample_ptr upsample = (my_upsample_ptr) cinfo->upsample; /* Just do the upsampling. */ (*upsample->upmethod) (cinfo, input_buf, *in_row_group_ctr, output_buf + *out_row_ctr); /* Adjust counts */ (*out_row_ctr)++; (*in_row_group_ctr)++; } /* * These are the routines invoked by the control routines to do * the actual upsampling/conversion. One row group is processed per call. * * Note: since we may be writing directly into application-supplied buffers, * we have to be honest about the output width; we can't assume the buffer * has been rounded up to an even width. */ /* * Upsample and color convert for the case of 2:1 horizontal and 1:1 vertical. */ METHODDEF(void) h2v1_merged_upsample (j_decompress_ptr cinfo, JSAMPIMAGE input_buf, JDIMENSION in_row_group_ctr, JSAMPARRAY output_buf) { my_upsample_ptr upsample = (my_upsample_ptr) cinfo->upsample; register int y, cred, cgreen, cblue; int cb, cr; register JSAMPROW outptr; JSAMPROW inptr0, inptr1, inptr2; JDIMENSION col; /* copy these pointers into registers if possible */ register JSAMPLE * range_limit = cinfo->sample_range_limit; int * Crrtab = upsample->Cr_r_tab; int * Cbbtab = upsample->Cb_b_tab; INT32 * Crgtab = upsample->Cr_g_tab; INT32 * Cbgtab = upsample->Cb_g_tab; SHIFT_TEMPS inptr0 = input_buf[0][in_row_group_ctr]; inptr1 = input_buf[1][in_row_group_ctr]; inptr2 = input_buf[2][in_row_group_ctr]; outptr = output_buf[0]; /* Loop for each pair of output pixels */ for (col = cinfo->output_width >> 1; col > 0; col--) { /* Do the chroma part of the calculation */ cb = GETJSAMPLE(*inptr1++); cr = GETJSAMPLE(*inptr2++); cred = Crrtab[cr]; cgreen = (int) RIGHT_SHIFT(Cbgtab[cb] + Crgtab[cr], SCALEBITS); cblue = Cbbtab[cb]; /* Fetch 2 Y values and emit 2 pixels */ y = GETJSAMPLE(*inptr0++); outptr[RGB_RED] = range_limit[y + cred]; outptr[RGB_GREEN] = range_limit[y + cgreen]; outptr[RGB_BLUE] = range_limit[y + cblue]; outptr += RGB_PIXELSIZE; y = GETJSAMPLE(*inptr0++); outptr[RGB_RED] = range_limit[y + cred]; outptr[RGB_GREEN] = range_limit[y + cgreen]; outptr[RGB_BLUE] = range_limit[y + cblue]; outptr += RGB_PIXELSIZE; } /* If image width is odd, do the last output column separately */ if (cinfo->output_width & 1) { cb = GETJSAMPLE(*inptr1); cr = GETJSAMPLE(*inptr2); cred = Crrtab[cr]; cgreen = (int) RIGHT_SHIFT(Cbgtab[cb] + Crgtab[cr], SCALEBITS); cblue = Cbbtab[cb]; y = GETJSAMPLE(*inptr0); outptr[RGB_RED] = range_limit[y + cred]; outptr[RGB_GREEN] = range_limit[y + cgreen]; outptr[RGB_BLUE] = range_limit[y + cblue]; } } /* * Upsample and color convert for the case of 2:1 horizontal and 2:1 vertical. */ METHODDEF(void) h2v2_merged_upsample (j_decompress_ptr cinfo, JSAMPIMAGE input_buf, JDIMENSION in_row_group_ctr, JSAMPARRAY output_buf) { my_upsample_ptr upsample = (my_upsample_ptr) cinfo->upsample; register int y, cred, cgreen, cblue; int cb, cr; register JSAMPROW outptr0, outptr1; JSAMPROW inptr00, inptr01, inptr1, inptr2; JDIMENSION col; /* copy these pointers into registers if possible */ register JSAMPLE * range_limit = cinfo->sample_range_limit; int * Crrtab = upsample->Cr_r_tab; int * Cbbtab = upsample->Cb_b_tab; INT32 * Crgtab = upsample->Cr_g_tab; INT32 * Cbgtab = upsample->Cb_g_tab; SHIFT_TEMPS inptr00 = input_buf[0][in_row_group_ctr*2]; inptr01 = input_buf[0][in_row_group_ctr*2 + 1]; inptr1 = input_buf[1][in_row_group_ctr]; inptr2 = input_buf[2][in_row_group_ctr]; outptr0 = output_buf[0]; outptr1 = output_buf[1]; /* Loop for each group of output pixels */ for (col = cinfo->output_width >> 1; col > 0; col--) { /* Do the chroma part of the calculation */ cb = GETJSAMPLE(*inptr1++); cr = GETJSAMPLE(*inptr2++); cred = Crrtab[cr]; cgreen = (int) RIGHT_SHIFT(Cbgtab[cb] + Crgtab[cr], SCALEBITS); cblue = Cbbtab[cb]; /* Fetch 4 Y values and emit 4 pixels */ y = GETJSAMPLE(*inptr00++); outptr0[RGB_RED] = range_limit[y + cred]; outptr0[RGB_GREEN] = range_limit[y + cgreen]; outptr0[RGB_BLUE] = range_limit[y + cblue]; outptr0 += RGB_PIXELSIZE; y = GETJSAMPLE(*inptr00++); outptr0[RGB_RED] = range_limit[y + cred]; outptr0[RGB_GREEN] = range_limit[y + cgreen]; outptr0[RGB_BLUE] = range_limit[y + cblue]; outptr0 += RGB_PIXELSIZE; y = GETJSAMPLE(*inptr01++); outptr1[RGB_RED] = range_limit[y + cred]; outptr1[RGB_GREEN] = range_limit[y + cgreen]; outptr1[RGB_BLUE] = range_limit[y + cblue]; outptr1 += RGB_PIXELSIZE; y = GETJSAMPLE(*inptr01++); outptr1[RGB_RED] = range_limit[y + cred]; outptr1[RGB_GREEN] = range_limit[y + cgreen]; outptr1[RGB_BLUE] = range_limit[y + cblue]; outptr1 += RGB_PIXELSIZE; } /* If image width is odd, do the last output column separately */ if (cinfo->output_width & 1) { cb = GETJSAMPLE(*inptr1); cr = GETJSAMPLE(*inptr2); cred = Crrtab[cr]; cgreen = (int) RIGHT_SHIFT(Cbgtab[cb] + Crgtab[cr], SCALEBITS); cblue = Cbbtab[cb]; y = GETJSAMPLE(*inptr00); outptr0[RGB_RED] = range_limit[y + cred]; outptr0[RGB_GREEN] = range_limit[y + cgreen]; outptr0[RGB_BLUE] = range_limit[y + cblue]; y = GETJSAMPLE(*inptr01); outptr1[RGB_RED] = range_limit[y + cred]; outptr1[RGB_GREEN] = range_limit[y + cgreen]; outptr1[RGB_BLUE] = range_limit[y + cblue]; } } /* * Module initialization routine for merged upsampling/color conversion. * * NB: this is called under the conditions determined by use_merged_upsample() * in jdmaster.c. That routine MUST correspond to the actual capabilities * of this module; no safety checks are made here. */ GLOBAL(void) jinit_merged_upsampler (j_decompress_ptr cinfo) { my_upsample_ptr upsample; upsample = (my_upsample_ptr) (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE, SIZEOF(my_upsampler)); cinfo->upsample = (struct jpeg_upsampler *) upsample; upsample->pub.start_pass = start_pass_merged_upsample; upsample->pub.need_context_rows = FALSE; upsample->out_row_width = cinfo->output_width * cinfo->out_color_components; if (cinfo->max_v_samp_factor == 2) { upsample->pub.upsample = merged_2v_upsample; upsample->upmethod = h2v2_merged_upsample; /* Allocate a spare row buffer */ upsample->spare_row = (JSAMPROW) (*cinfo->mem->alloc_large) ((j_common_ptr) cinfo, JPOOL_IMAGE, (size_t) (upsample->out_row_width * SIZEOF(JSAMPLE))); } else { upsample->pub.upsample = merged_1v_upsample; upsample->upmethod = h2v1_merged_upsample; /* No spare row needed */ upsample->spare_row = NULL; } build_ycc_rgb_table(cinfo); } #endif /* UPSAMPLE_MERGING_SUPPORTED */

Details