libavcodec/libxvidff.c

   1 /*
   2  * Interface to xvidcore for mpeg4 encoding
   3  * Copyright (c) 2004 Adam Thayer <krevnik@comcast.net>
   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 libavcodec/libxvidff.c
  24  * Interface to xvidcore for MPEG-4 compliant encoding.
  25  * @author Adam Thayer (krevnik@comcast.net)
  26  */
  27
  28 #include <xvid.h>
  29 #include <unistd.h>
  30 #include "avcodec.h"
  31 #include "libavutil/intreadwrite.h"
  32 #include "libxvid_internal.h"
  33
  34 /**
  35  * Buffer management macros.
  36  */
  37 #define BUFFER_SIZE                 1024
  38 #define BUFFER_REMAINING(x)         (BUFFER_SIZE - strlen(x))
  39 #define BUFFER_CAT(x)               (&((x)[strlen(x)]))
  40
  41 /* For PPC Use */
  42 int has_altivec(void);
  43
  44 /**
  45  * Structure for the private Xvid context.
  46  * This stores all the private context for the codec.
  47  */
  48 struct xvid_context {
  49     void *encoder_handle;          /** Handle for Xvid encoder */
  50     int xsize, ysize;              /** Frame size */
  51     int vop_flags;                 /** VOP flags for Xvid encoder */
  52     int vol_flags;                 /** VOL flags for Xvid encoder */
  53     int me_flags;                  /** Motion Estimation flags */
  54     int qscale;                    /** Do we use constant scale? */
  55     int quicktime_format;          /** Are we in a QT-based format? */
  56     AVFrame encoded_picture;       /** Encoded frame information */
  57     char *twopassbuffer;           /** Character buffer for two-pass */
  58     char *old_twopassbuffer;       /** Old character buffer (two-pass) */
  59     char *twopassfile;             /** second pass temp file name */
  60     unsigned char *intra_matrix;   /** P-Frame Quant Matrix */
  61     unsigned char *inter_matrix;   /** I-Frame Quant Matrix */
  62 };
  63
  64 /**
  65  * Structure for the private first-pass plugin.
  66  */
  67 struct xvid_ff_pass1 {
  68     int     version;                /** Xvid version */
  69     struct xvid_context *context;        /** Pointer to private context */
  70 };
  71
  72 /* Prototypes - See function implementation for details */
  73 int xvid_strip_vol_header(AVCodecContext *avctx, unsigned char *frame, unsigned int header_len, unsigned int frame_len);
  74 int xvid_ff_2pass(void *ref, int opt, void *p1, void *p2);
  75 void xvid_correct_framerate(AVCodecContext *avctx);
  76
  77 /**
  78  * Creates the private context for the encoder.
  79  * All buffers are allocated, settings are loaded from the user,
  80  * and the encoder context created.
  81  *
  82  * @param avctx AVCodecContext pointer to context
  83  * @return Returns 0 on success, -1 on failure
  84  */
  85 av_cold int ff_xvid_encode_init(AVCodecContext *avctx)  {
  86     int xerr, i;
  87     int xvid_flags = avctx->flags;
  88     struct xvid_context *x = avctx->priv_data;
  89     uint16_t *intra, *inter;
  90     int fd;
  91
  92     xvid_plugin_single_t single;
  93     struct xvid_ff_pass1 rc2pass1;
  94     xvid_plugin_2pass2_t rc2pass2;
  95     xvid_gbl_init_t xvid_gbl_init;
  96     xvid_enc_create_t xvid_enc_create;
  97     xvid_enc_plugin_t plugins[7];
  98
  99     /* Bring in VOP flags from ffmpeg command-line */
 100     x->vop_flags = XVID_VOP_HALFPEL; /* Bare minimum quality */
 101     if( xvid_flags & CODEC_FLAG_4MV )
 102         x->vop_flags |= XVID_VOP_INTER4V; /* Level 3 */
 103     if( avctx->trellis
 104         )
 105         x->vop_flags |= XVID_VOP_TRELLISQUANT; /* Level 5 */
 106     if( xvid_flags & CODEC_FLAG_AC_PRED )
 107         x->vop_flags |= XVID_VOP_HQACPRED; /* Level 6 */
 108     if( xvid_flags & CODEC_FLAG_GRAY )
 109         x->vop_flags |= XVID_VOP_GREYSCALE;
 110
 111     /* Decide which ME quality setting to use */
 112     x->me_flags = 0;
 113     switch( avctx->me_method ) {
 114        case ME_FULL:   /* Quality 6 */
 115            x->me_flags |=  XVID_ME_EXTSEARCH16
 116                        |   XVID_ME_EXTSEARCH8;
 117
 118        case ME_EPZS:   /* Quality 4 */
 119            x->me_flags |=  XVID_ME_ADVANCEDDIAMOND8
 120                        |   XVID_ME_HALFPELREFINE8
 121                        |   XVID_ME_CHROMA_PVOP
 122                        |   XVID_ME_CHROMA_BVOP;
 123
 124        case ME_LOG:    /* Quality 2 */
 125        case ME_PHODS:
 126        case ME_X1:
 127            x->me_flags |=  XVID_ME_ADVANCEDDIAMOND16
 128                        |   XVID_ME_HALFPELREFINE16;
 129
 130        case ME_ZERO:   /* Quality 0 */
 131        default:
 132            break;
 133     }
 134
 135     /* Decide how we should decide blocks */
 136     switch( avctx->mb_decision ) {
 137        case 2:
 138            x->vop_flags |= XVID_VOP_MODEDECISION_RD;
 139            x->me_flags |=  XVID_ME_HALFPELREFINE8_RD
 140                        |   XVID_ME_QUARTERPELREFINE8_RD
 141                        |   XVID_ME_EXTSEARCH_RD
 142                        |   XVID_ME_CHECKPREDICTION_RD;
 143        case 1:
 144            if( !(x->vop_flags & XVID_VOP_MODEDECISION_RD) )
 145                x->vop_flags |= XVID_VOP_FAST_MODEDECISION_RD;
 146            x->me_flags |=  XVID_ME_HALFPELREFINE16_RD
 147                        |   XVID_ME_QUARTERPELREFINE16_RD;
 148
 149        default:
 150            break;
 151     }
 152
 153     /* Bring in VOL flags from ffmpeg command-line */
 154     x->vol_flags = 0;
 155     if( xvid_flags & CODEC_FLAG_GMC ) {
 156         x->vol_flags |= XVID_VOL_GMC;
 157         x->me_flags |= XVID_ME_GME_REFINE;
 158     }
 159     if( xvid_flags & CODEC_FLAG_QPEL ) {
 160         x->vol_flags |= XVID_VOL_QUARTERPEL;
 161         x->me_flags |= XVID_ME_QUARTERPELREFINE16;
 162         if( x->vop_flags & XVID_VOP_INTER4V )
 163             x->me_flags |= XVID_ME_QUARTERPELREFINE8;
 164     }
 165
 166     memset(&xvid_gbl_init, 0, sizeof(xvid_gbl_init));
 167     xvid_gbl_init.version = XVID_VERSION;
 168     xvid_gbl_init.debug = 0;
 169
 170 #if ARCH_PPC
 171     /* Xvid's PPC support is borked, use libavcodec to detect */
 172 #if HAVE_ALTIVEC
 173     if( has_altivec() ) {
 174         xvid_gbl_init.cpu_flags = XVID_CPU_FORCE | XVID_CPU_ALTIVEC;
 175     } else
 176 #endif
 177         xvid_gbl_init.cpu_flags = XVID_CPU_FORCE;
 178 #else
 179     /* Xvid can detect on x86 */
 180     xvid_gbl_init.cpu_flags = 0;
 181 #endif
 182
 183     /* Initialize */
 184     xvid_global(NULL, XVID_GBL_INIT, &xvid_gbl_init, NULL);
 185
 186     /* Create the encoder reference */
 187     memset(&xvid_enc_create, 0, sizeof(xvid_enc_create));
 188     xvid_enc_create.version = XVID_VERSION;
 189
 190     /* Store the desired frame size */
 191     xvid_enc_create.width = x->xsize = avctx->width;
 192     xvid_enc_create.height = x->ysize = avctx->height;
 193
 194     /* Xvid can determine the proper profile to use */
 195     /* xvid_enc_create.profile = XVID_PROFILE_S_L3; */
 196
 197     /* We don't use zones */
 198     xvid_enc_create.zones = NULL;
 199     xvid_enc_create.num_zones = 0;
 200
 201     xvid_enc_create.num_threads = avctx->thread_count;
 202
 203     xvid_enc_create.plugins = plugins;
 204     xvid_enc_create.num_plugins = 0;
 205
 206     /* Initialize Buffers */
 207     x->twopassbuffer = NULL;
 208     x->old_twopassbuffer = NULL;
 209     x->twopassfile = NULL;
 210
 211     if( xvid_flags & CODEC_FLAG_PASS1 ) {
 212         memset(&rc2pass1, 0, sizeof(struct xvid_ff_pass1));
 213         rc2pass1.version = XVID_VERSION;
 214         rc2pass1.context = x;
 215         x->twopassbuffer = av_malloc(BUFFER_SIZE);
 216         x->old_twopassbuffer = av_malloc(BUFFER_SIZE);
 217         if( x->twopassbuffer == NULL || x->old_twopassbuffer == NULL ) {
 218             av_log(avctx, AV_LOG_ERROR,
 219                 "Xvid: Cannot allocate 2-pass log buffers\n");
 220             return -1;
 221         }
 222         x->twopassbuffer[0] = x->old_twopassbuffer[0] = 0;
 223
 224         plugins[xvid_enc_create.num_plugins].func = xvid_ff_2pass;
 225         plugins[xvid_enc_create.num_plugins].param = &rc2pass1;
 226         xvid_enc_create.num_plugins++;
 227     } else if( xvid_flags & CODEC_FLAG_PASS2 ) {
 228         memset(&rc2pass2, 0, sizeof(xvid_plugin_2pass2_t));
 229         rc2pass2.version = XVID_VERSION;
 230         rc2pass2.bitrate = avctx->bit_rate;
 231
 232         fd = av_tempfile("xvidff.", &(x->twopassfile));
 233         if( fd == -1 ) {
 234             av_log(avctx, AV_LOG_ERROR,
 235                 "Xvid: Cannot write 2-pass pipe\n");
 236             return -1;
 237         }
 238
 239         if( avctx->stats_in == NULL ) {
 240             av_log(avctx, AV_LOG_ERROR,
 241                 "Xvid: No 2-pass information loaded for second pass\n");
 242             return -1;
 243         }
 244
 245         if( strlen(avctx->stats_in) >
 246               write(fd, avctx->stats_in, strlen(avctx->stats_in)) ) {
 247             close(fd);
 248             av_log(avctx, AV_LOG_ERROR,
 249                 "Xvid: Cannot write to 2-pass pipe\n");
 250             return -1;
 251         }
 252
 253         close(fd);
 254         rc2pass2.filename = x->twopassfile;
 255         plugins[xvid_enc_create.num_plugins].func = xvid_plugin_2pass2;
 256         plugins[xvid_enc_create.num_plugins].param = &rc2pass2;
 257         xvid_enc_create.num_plugins++;
 258     } else if( !(xvid_flags & CODEC_FLAG_QSCALE) ) {
 259         /* Single Pass Bitrate Control! */
 260         memset(&single, 0, sizeof(xvid_plugin_single_t));
 261         single.version = XVID_VERSION;
 262         single.bitrate = avctx->bit_rate;
 263
 264         plugins[xvid_enc_create.num_plugins].func = xvid_plugin_single;
 265         plugins[xvid_enc_create.num_plugins].param = &single;
 266         xvid_enc_create.num_plugins++;
 267     }
 268
 269     /* Luminance Masking */
 270     if( 0.0 != avctx->lumi_masking ) {
 271         plugins[xvid_enc_create.num_plugins].func = xvid_plugin_lumimasking;
 272         plugins[xvid_enc_create.num_plugins].param = NULL;
 273         xvid_enc_create.num_plugins++;
 274     }
 275
 276     /* Frame Rate and Key Frames */
 277     xvid_correct_framerate(avctx);
 278     xvid_enc_create.fincr = avctx->time_base.num;
 279     xvid_enc_create.fbase = avctx->time_base.den;
 280     if( avctx->gop_size > 0 )
 281         xvid_enc_create.max_key_interval = avctx->gop_size;
 282     else
 283         xvid_enc_create.max_key_interval = 240; /* Xvid's best default */
 284
 285     /* Quants */
 286     if( xvid_flags & CODEC_FLAG_QSCALE ) x->qscale = 1;
 287     else x->qscale = 0;
 288
 289     xvid_enc_create.min_quant[0] = avctx->qmin;
 290     xvid_enc_create.min_quant[1] = avctx->qmin;
 291     xvid_enc_create.min_quant[2] = avctx->qmin;
 292     xvid_enc_create.max_quant[0] = avctx->qmax;
 293     xvid_enc_create.max_quant[1] = avctx->qmax;
 294     xvid_enc_create.max_quant[2] = avctx->qmax;
 295
 296     /* Quant Matrices */
 297     x->intra_matrix = x->inter_matrix = NULL;
 298     if( avctx->mpeg_quant )
 299        x->vol_flags |= XVID_VOL_MPEGQUANT;
 300     if( (avctx->intra_matrix || avctx->inter_matrix) ) {
 301        x->vol_flags |= XVID_VOL_MPEGQUANT;
 302
 303        if( avctx->intra_matrix ) {
 304            intra = avctx->intra_matrix;
 305            x->intra_matrix = av_malloc(sizeof(unsigned char) * 64);
 306        } else
 307            intra = NULL;
 308        if( avctx->inter_matrix ) {
 309            inter = avctx->inter_matrix;
 310            x->inter_matrix = av_malloc(sizeof(unsigned char) * 64);
 311        } else
 312            inter = NULL;
 313
 314        for( i = 0; i < 64; i++ ) {
 315            if( intra )
 316                x->intra_matrix[i] = (unsigned char)intra[i];
 317            if( inter )
 318                x->inter_matrix[i] = (unsigned char)inter[i];
 319        }
 320     }
 321
 322     /* Misc Settings */
 323     xvid_enc_create.frame_drop_ratio = 0;
 324     xvid_enc_create.global = 0;
 325     if( xvid_flags & CODEC_FLAG_CLOSED_GOP )
 326         xvid_enc_create.global |= XVID_GLOBAL_CLOSED_GOP;
 327
 328     /* Determines which codec mode we are operating in */
 329     avctx->extradata = NULL;
 330     avctx->extradata_size = 0;
 331     if( xvid_flags & CODEC_FLAG_GLOBAL_HEADER ) {
 332         /* In this case, we are claiming to be MPEG4 */
 333         x->quicktime_format = 1;
 334         avctx->codec_id = CODEC_ID_MPEG4;
 335     } else {
 336         /* We are claiming to be Xvid */
 337         x->quicktime_format = 0;
 338         if(!avctx->codec_tag)
 339             avctx->codec_tag = AV_RL32("xvid");
 340     }
 341
 342     /* Bframes */
 343     xvid_enc_create.max_bframes = avctx->max_b_frames;
 344     xvid_enc_create.bquant_offset = 100 * avctx->b_quant_offset;
 345     xvid_enc_create.bquant_ratio = 100 * avctx->b_quant_factor;
 346     if( avctx->max_b_frames > 0  && !x->quicktime_format ) xvid_enc_create.global |= XVID_GLOBAL_PACKED;
 347
 348     /* Create encoder context */
 349     xerr = xvid_encore(NULL, XVID_ENC_CREATE, &xvid_enc_create, NULL);
 350     if( xerr ) {
 351         av_log(avctx, AV_LOG_ERROR, "Xvid: Could not create encoder reference\n");
 352         return -1;
 353     }
 354
 355     x->encoder_handle = xvid_enc_create.handle;
 356     avctx->coded_frame = &x->encoded_picture;
 357
 358     return 0;
 359 }
 360
 361 /**
 362  * Encodes a single frame.
 363  *
 364  * @param avctx AVCodecContext pointer to context
 365  * @param frame Pointer to encoded frame buffer
 366  * @param buf_size Size of encoded frame buffer
 367  * @param data Pointer to AVFrame of unencoded frame
 368  * @return Returns 0 on success, -1 on failure
 369  */
 370 int ff_xvid_encode_frame(AVCodecContext *avctx,
 371                          unsigned char *frame, int buf_size, void *data) {
 372     int xerr, i;
 373     char *tmp;
 374     struct xvid_context *x = avctx->priv_data;
 375     AVFrame *picture = data;
 376     AVFrame *p = &(x->encoded_picture);
 377
 378     xvid_enc_frame_t xvid_enc_frame;
 379     xvid_enc_stats_t xvid_enc_stats;
 380
 381     /* Start setting up the frame */
 382     memset(&xvid_enc_frame, 0, sizeof(xvid_enc_frame));
 383     xvid_enc_frame.version = XVID_VERSION;
 384     memset(&xvid_enc_stats, 0, sizeof(xvid_enc_stats));
 385     xvid_enc_stats.version = XVID_VERSION;
 386     *p = *picture;
 387
 388     /* Let Xvid know where to put the frame. */
 389     xvid_enc_frame.bitstream = frame;
 390     xvid_enc_frame.length = buf_size;
 391
 392     /* Initialize input image fields */
 393     if( avctx->pix_fmt != PIX_FMT_YUV420P ) {
 394         av_log(avctx, AV_LOG_ERROR, "Xvid: Color spaces other than 420p not supported\n");
 395         return -1;
 396     }
 397
 398     xvid_enc_frame.input.csp = XVID_CSP_PLANAR; /* YUV420P */
 399
 400     for( i = 0; i < 4; i++ ) {
 401         xvid_enc_frame.input.plane[i] = picture->data[i];
 402         xvid_enc_frame.input.stride[i] = picture->linesize[i];
 403     }
 404
 405     /* Encoder Flags */
 406     xvid_enc_frame.vop_flags = x->vop_flags;
 407     xvid_enc_frame.vol_flags = x->vol_flags;
 408     xvid_enc_frame.motion = x->me_flags;
 409     xvid_enc_frame.type = XVID_TYPE_AUTO;
 410
 411     /* Pixel aspect ratio setting */
 412     if (avctx->sample_aspect_ratio.num < 1 || avctx->sample_aspect_ratio.num > 255 ||
 413         avctx->sample_aspect_ratio.den < 1 || avctx->sample_aspect_ratio.den > 255) {
 414         av_log(avctx, AV_LOG_ERROR, "Invalid pixel aspect ratio %i/%i\n",
 415                avctx->sample_aspect_ratio.num, avctx->sample_aspect_ratio.den);
 416         return -1;
 417     }
 418     xvid_enc_frame.par = XVID_PAR_EXT;
 419     xvid_enc_frame.par_width  = avctx->sample_aspect_ratio.num;
 420     xvid_enc_frame.par_height = avctx->sample_aspect_ratio.den;
 421
 422     /* Quant Setting */
 423     if( x->qscale ) xvid_enc_frame.quant = picture->quality / FF_QP2LAMBDA;
 424     else xvid_enc_frame.quant = 0;
 425
 426     /* Matrices */
 427     xvid_enc_frame.quant_intra_matrix = x->intra_matrix;
 428     xvid_enc_frame.quant_inter_matrix = x->inter_matrix;
 429
 430     /* Encode */
 431     xerr = xvid_encore(x->encoder_handle, XVID_ENC_ENCODE,
 432         &xvid_enc_frame, &xvid_enc_stats);
 433
 434     /* Two-pass log buffer swapping */
 435     avctx->stats_out = NULL;
 436     if( x->twopassbuffer ) {
 437         tmp = x->old_twopassbuffer;
 438         x->old_twopassbuffer = x->twopassbuffer;
 439         x->twopassbuffer = tmp;
 440         x->twopassbuffer[0] = 0;
 441         if( x->old_twopassbuffer[0] != 0 ) {
 442             avctx->stats_out = x->old_twopassbuffer;
 443         }
 444     }
 445
 446     if( 0 <= xerr ) {
 447         p->quality = xvid_enc_stats.quant * FF_QP2LAMBDA;
 448         if( xvid_enc_stats.type == XVID_TYPE_PVOP )
 449             p->pict_type = FF_P_TYPE;
 450         else if( xvid_enc_stats.type == XVID_TYPE_BVOP )
 451             p->pict_type = FF_B_TYPE;
 452         else if( xvid_enc_stats.type == XVID_TYPE_SVOP )
 453             p->pict_type = FF_S_TYPE;
 454         else
 455             p->pict_type = FF_I_TYPE;
 456         if( xvid_enc_frame.out_flags & XVID_KEYFRAME ) {
 457             p->key_frame = 1;
 458             if( x->quicktime_format )
 459                 return xvid_strip_vol_header(avctx, frame,
 460                     xvid_enc_stats.hlength, xerr);
 461          } else
 462             p->key_frame = 0;
 463
 464         return xerr;
 465     } else {
 466         av_log(avctx, AV_LOG_ERROR, "Xvid: Encoding Error Occurred: %i\n", xerr);
 467         return -1;
 468     }
 469 }
 470
 471 /**
 472  * Destroys the private context for the encoder.
 473  * All buffers are freed, and the Xvid encoder context is destroyed.
 474  *
 475  * @param avctx AVCodecContext pointer to context
 476  * @return Returns 0, success guaranteed
 477  */
 478 av_cold int ff_xvid_encode_close(AVCodecContext *avctx) {
 479     struct xvid_context *x = avctx->priv_data;
 480
 481     xvid_encore(x->encoder_handle, XVID_ENC_DESTROY, NULL, NULL);
 482
 483     if( avctx->extradata != NULL )
 484         av_free(avctx->extradata);
 485     if( x->twopassbuffer != NULL ) {
 486         av_free(x->twopassbuffer);
 487         av_free(x->old_twopassbuffer);
 488     }
 489     if( x->twopassfile != NULL )
 490         av_free(x->twopassfile);
 491     if( x->intra_matrix != NULL )
 492         av_free(x->intra_matrix);
 493     if( x->inter_matrix != NULL )
 494         av_free(x->inter_matrix);
 495
 496     return 0;
 497 }
 498
 499 /**
 500  * Routine to create a global VO/VOL header for MP4 container.
 501  * What we do here is extract the header from the Xvid bitstream
 502  * as it is encoded. We also strip the repeated headers from the
 503  * bitstream when a global header is requested for MPEG-4 ISO
 504  * compliance.
 505  *
 506  * @param avctx AVCodecContext pointer to context
 507  * @param frame Pointer to encoded frame data
 508  * @param header_len Length of header to search
 509  * @param frame_len Length of encoded frame data
 510  * @return Returns new length of frame data
 511  */
 512 int xvid_strip_vol_header(AVCodecContext *avctx,
 513                   unsigned char *frame,
 514                   unsigned int header_len,
 515                   unsigned int frame_len) {
 516     int vo_len = 0, i;
 517
 518     for( i = 0; i < header_len - 3; i++ ) {
 519         if( frame[i] == 0x00 &&
 520             frame[i+1] == 0x00 &&
 521             frame[i+2] == 0x01 &&
 522             frame[i+3] == 0xB6 ) {
 523             vo_len = i;
 524             break;
 525         }
 526     }
 527
 528     if( vo_len > 0 ) {
 529         /* We need to store the header, so extract it */
 530         if( avctx->extradata == NULL ) {
 531             avctx->extradata = av_malloc(vo_len);
 532             memcpy(avctx->extradata, frame, vo_len);
 533             avctx->extradata_size = vo_len;
 534         }
 535         /* Less dangerous now, memmove properly copies the two
 536            chunks of overlapping data */
 537         memmove(frame, &(frame[vo_len]), frame_len - vo_len);
 538         return frame_len - vo_len;
 539     } else
 540         return frame_len;
 541 }
 542
 543 /**
 544  * Routine to correct a possibly erroneous framerate being fed to us.
 545  * Xvid currently chokes on framerates where the ticks per frame is
 546  * extremely large. This function works to correct problems in this area
 547  * by estimating a new framerate and taking the simpler fraction of
 548  * the two presented.
 549  *
 550  * @param avctx Context that contains the framerate to correct.
 551  */
 552 void xvid_correct_framerate(AVCodecContext *avctx) {
 553     int frate, fbase;
 554     int est_frate, est_fbase;
 555     int gcd;
 556     float est_fps, fps;
 557
 558     frate = avctx->time_base.den;
 559     fbase = avctx->time_base.num;
 560
 561     gcd = av_gcd(frate, fbase);
 562     if( gcd > 1 ) {
 563         frate /= gcd;
 564         fbase /= gcd;
 565     }
 566
 567     if( frate <= 65000 && fbase <= 65000 ) {
 568         avctx->time_base.den = frate;
 569         avctx->time_base.num = fbase;
 570         return;
 571     }
 572
 573     fps = (float)frate / (float)fbase;
 574     est_fps = roundf(fps * 1000.0) / 1000.0;
 575
 576     est_frate = (int)est_fps;
 577     if( est_fps > (int)est_fps ) {
 578         est_frate = (est_frate + 1) * 1000;
 579         est_fbase = (int)roundf((float)est_frate / est_fps);
 580     } else
 581         est_fbase = 1;
 582
 583     gcd = av_gcd(est_frate, est_fbase);
 584     if( gcd > 1 ) {
 585         est_frate /= gcd;
 586         est_fbase /= gcd;
 587     }
 588
 589     if( fbase > est_fbase ) {
 590         avctx->time_base.den = est_frate;
 591         avctx->time_base.num = est_fbase;
 592         av_log(avctx, AV_LOG_DEBUG,
 593             "Xvid: framerate re-estimated: %.2f, %.3f%% correction\n",
 594             est_fps, (((est_fps - fps)/fps) * 100.0));
 595     } else {
 596         avctx->time_base.den = frate;
 597         avctx->time_base.num = fbase;
 598     }
 599 }
 600
 601 /*
 602  * Xvid 2-Pass Kludge Section
 603  *
 604  * Xvid's default 2-pass doesn't allow us to create data as we need to, so
 605  * this section spends time replacing the first pass plugin so we can write
 606  * statistic information as libavcodec requests in. We have another kludge
 607  * that allows us to pass data to the second pass in Xvid without a custom
 608  * rate-control plugin.
 609  */
 610
 611 /**
 612  * Initializes the two-pass plugin and context.
 613  *
 614  * @param param Input construction parameter structure
 615  * @param handle Private context handle
 616  * @return Returns XVID_ERR_xxxx on failure, or 0 on success.
 617  */
 618 static int xvid_ff_2pass_create(xvid_plg_create_t * param,
 619                                 void ** handle) {
 620     struct xvid_ff_pass1 *x = (struct xvid_ff_pass1 *)param->param;
 621     char *log = x->context->twopassbuffer;
 622
 623     /* Do a quick bounds check */
 624     if( log == NULL )
 625         return XVID_ERR_FAIL;
 626
 627     /* We use snprintf() */
 628     /* This is because we can safely prevent a buffer overflow */
 629     log[0] = 0;
 630     snprintf(log, BUFFER_REMAINING(log),
 631         "# ffmpeg 2-pass log file, using xvid codec\n");
 632     snprintf(BUFFER_CAT(log), BUFFER_REMAINING(log),
 633         "# Do not modify. libxvidcore version: %d.%d.%d\n\n",
 634         XVID_VERSION_MAJOR(XVID_VERSION),
 635         XVID_VERSION_MINOR(XVID_VERSION),
 636         XVID_VERSION_PATCH(XVID_VERSION));
 637
 638     *handle = x->context;
 639     return 0;
 640 }
 641
 642 /**
 643  * Destroys the two-pass plugin context.
 644  *
 645  * @param ref Context pointer for the plugin
 646  * @param param Destrooy context
 647  * @return Returns 0, success guaranteed
 648  */
 649 static int xvid_ff_2pass_destroy(struct xvid_context *ref,
 650                                 xvid_plg_destroy_t *param) {
 651     /* Currently cannot think of anything to do on destruction */
 652     /* Still, the framework should be here for reference/use */
 653     if( ref->twopassbuffer != NULL )
 654         ref->twopassbuffer[0] = 0;
 655     return 0;
 656 }
 657
 658 /**
 659  * Enables fast encode mode during the first pass.
 660  *
 661  * @param ref Context pointer for the plugin
 662  * @param param Frame data
 663  * @return Returns 0, success guaranteed
 664  */
 665 static int xvid_ff_2pass_before(struct xvid_context *ref,
 666                                 xvid_plg_data_t *param) {
 667     int motion_remove;
 668     int motion_replacements;
 669     int vop_remove;
 670
 671     /* Nothing to do here, result is changed too much */
 672     if( param->zone && param->zone->mode == XVID_ZONE_QUANT )
 673         return 0;
 674
 675     /* We can implement a 'turbo' first pass mode here */
 676     param->quant = 2;
 677
 678     /* Init values */
 679     motion_remove = ~XVID_ME_CHROMA_PVOP &
 680                     ~XVID_ME_CHROMA_BVOP &
 681                     ~XVID_ME_EXTSEARCH16 &
 682                     ~XVID_ME_ADVANCEDDIAMOND16;
 683     motion_replacements = XVID_ME_FAST_MODEINTERPOLATE |
 684                           XVID_ME_SKIP_DELTASEARCH |
 685                           XVID_ME_FASTREFINE16 |
 686                           XVID_ME_BFRAME_EARLYSTOP;
 687     vop_remove = ~XVID_VOP_MODEDECISION_RD &
 688                  ~XVID_VOP_FAST_MODEDECISION_RD &
 689                  ~XVID_VOP_TRELLISQUANT &
 690                  ~XVID_VOP_INTER4V &
 691                  ~XVID_VOP_HQACPRED;
 692
 693     param->vol_flags &= ~XVID_VOL_GMC;
 694     param->vop_flags &= vop_remove;
 695     param->motion_flags &= motion_remove;
 696     param->motion_flags |= motion_replacements;
 697
 698     return 0;
 699 }
 700
 701 /**
 702  * Captures statistic data and writes it during first pass.
 703  *
 704  * @param ref Context pointer for the plugin
 705  * @param param Statistic data
 706  * @return Returns XVID_ERR_xxxx on failure, or 0 on success
 707  */
 708 static int xvid_ff_2pass_after(struct xvid_context *ref,
 709                                 xvid_plg_data_t *param) {
 710     char *log = ref->twopassbuffer;
 711     char *frame_types = " ipbs";
 712     char frame_type;
 713
 714     /* Quick bounds check */
 715     if( log == NULL )
 716         return XVID_ERR_FAIL;
 717
 718     /* Convert the type given to us into a character */
 719     if( param->type < 5 && param->type > 0 ) {
 720         frame_type = frame_types[param->type];
 721     } else {
 722         return XVID_ERR_FAIL;
 723     }
 724
 725     snprintf(BUFFER_CAT(log), BUFFER_REMAINING(log),
 726         "%c %d %d %d %d %d %d\n",
 727         frame_type, param->stats.quant, param->stats.kblks, param->stats.mblks,
 728         param->stats.ublks, param->stats.length, param->stats.hlength);
 729
 730     return 0;
 731 }
 732
 733 /**
 734  * Dispatch function for our custom plugin.
 735  * This handles the dispatch for the Xvid plugin. It passes data
 736  * on to other functions for actual processing.
 737  *
 738  * @param ref Context pointer for the plugin
 739  * @param cmd The task given for us to complete
 740  * @param p1 First parameter (varies)
 741  * @param p2 Second parameter (varies)
 742  * @return Returns XVID_ERR_xxxx on failure, or 0 on success
 743  */
 744 int xvid_ff_2pass(void *ref, int cmd, void *p1, void *p2) {
 745     switch( cmd ) {
 746         case XVID_PLG_INFO:
 747         case XVID_PLG_FRAME:
 748             return 0;
 749
 750         case XVID_PLG_BEFORE:
 751             return xvid_ff_2pass_before(ref, p1);
 752
 753         case XVID_PLG_CREATE:
 754             return xvid_ff_2pass_create(p1, p2);
 755
 756         case XVID_PLG_AFTER:
 757             return xvid_ff_2pass_after(ref, p1);
 758
 759         case XVID_PLG_DESTROY:
 760             return xvid_ff_2pass_destroy(ref, p1);
 761
 762         default:
 763             return XVID_ERR_FAIL;
 764     }
 765 }
 766
 767 /**
 768  * Xvid codec definition for libavcodec.
 769  */
 770 AVCodec libxvid_encoder = {
 771     "libxvid",
 772     CODEC_TYPE_VIDEO,
 773     CODEC_ID_XVID,
 774     sizeof(struct xvid_context),
 775     ff_xvid_encode_init,
 776     ff_xvid_encode_frame,
 777     ff_xvid_encode_close,
 778     .pix_fmts= (enum PixelFormat[]){PIX_FMT_YUV420P, PIX_FMT_NONE},
 779     .long_name= NULL_IF_CONFIG_SMALL("libxvidcore MPEG-4 part 2"),
 780 };