Give all wrappers for external libraries names starting with lib.

Originally committed as revision 9226 to svn://svn.ffmpeg.org/ffmpeg/trunk

1 files changed, 767 insertions, 0 deletions

diff --git a/libavcodec/libxvidff.c b/libavcodec/libxvidff.c
new file mode 100644
index 0000000000..506af910be
--- /dev/null
+++ b/libavcodec/libxvidff.c
@@ -0,0 +1,767 @@
+/*
+ * Interface to xvidcore for mpeg4 encoding
+ * Copyright (c) 2004 Adam Thayer <krevnik@comcast.net>
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+/**
+ * @file xvidmpeg4.c
+ * Interface to xvidcore for MPEG-4 compliant encoding.
+ * @author Adam Thayer (krevnik@comcast.net)
+ */
+
+#include <xvid.h>
+#include <unistd.h>
+#include "avcodec.h"
+#include "libxvid_internal.h"
+
+/**
+ * Buffer management macros.
+ */
+#define BUFFER_SIZE                 1024
+#define BUFFER_REMAINING(x)         (BUFFER_SIZE - strlen(x))
+#define BUFFER_CAT(x)               (&((x)[strlen(x)]))
+
+/* For PPC Use */
+#if HAVE_ALTIVEC==1
+extern int has_altivec(void);
+#endif
+
+/**
+ * Structure for the private XviD context.
+ * This stores all the private context for the codec.
+ */
+typedef struct xvid_context {
+    void *encoder_handle;          /** Handle for XviD Encoder */
+    int xsize, ysize;              /** Frame size */
+    int vop_flags;                 /** VOP flags for XviD Encoder */
+    int vol_flags;                 /** VOL flags for XviD Encoder */
+    int me_flags;                  /** Motion Estimation flags */
+    int qscale;                    /** Do we use constant scale? */
+    int quicktime_format;          /** Are we in a QT-based format? */
+    AVFrame encoded_picture;       /** Encoded frame information */
+    char *twopassbuffer;           /** Character buffer for two-pass */
+    char *old_twopassbuffer;       /** Old character buffer (two-pass) */
+    char *twopassfile;             /** second pass temp file name */
+    unsigned char *intra_matrix;   /** P-Frame Quant Matrix */
+    unsigned char *inter_matrix;   /** I-Frame Quant Matrix */
+} xvid_context_t;
+
+/**
+ * Structure for the private first-pass plugin.
+ */
+typedef struct xvid_ff_pass1 {
+    int     version;                /** XviD version */
+    xvid_context_t *context;        /** Pointer to private context */
+} xvid_ff_pass1_t;
+
+/* Prototypes - See function implementation for details */
+int xvid_strip_vol_header(AVCodecContext *avctx, unsigned char *frame, unsigned int header_len, unsigned int frame_len);
+int xvid_ff_2pass(void *ref, int opt, void *p1, void *p2);
+void xvid_correct_framerate(AVCodecContext *avctx);
+
+/**
+ * Creates the private context for the encoder.
+ * All buffers are allocated, settings are loaded from the user,
+ * and the encoder context created.
+ *
+ * @param avctx AVCodecContext pointer to context
+ * @return Returns 0 on success, -1 on failure
+ */
+int ff_xvid_encode_init(AVCodecContext *avctx)  {
+    int xerr, i;
+    int xvid_flags = avctx->flags;
+    xvid_context_t *x = avctx->priv_data;
+    uint16_t *intra, *inter;
+    int fd;
+
+    xvid_plugin_single_t single;
+    xvid_ff_pass1_t rc2pass1;
+    xvid_plugin_2pass2_t rc2pass2;
+    xvid_gbl_init_t xvid_gbl_init;
+    xvid_enc_create_t xvid_enc_create;
+    xvid_enc_plugin_t plugins[7];
+
+    /* Bring in VOP flags from ffmpeg command-line */
+    x->vop_flags = XVID_VOP_HALFPEL; /* Bare minimum quality */
+    if( xvid_flags & CODEC_FLAG_4MV )
+        x->vop_flags |= XVID_VOP_INTER4V; /* Level 3 */
+    if( xvid_flags & CODEC_FLAG_TRELLIS_QUANT)
+        x->vop_flags |= XVID_VOP_TRELLISQUANT; /* Level 5 */
+    if( xvid_flags & CODEC_FLAG_AC_PRED )
+        x->vop_flags |= XVID_VOP_HQACPRED; /* Level 6 */
+    if( xvid_flags & CODEC_FLAG_GRAY )
+        x->vop_flags |= XVID_VOP_GREYSCALE;
+
+    /* Decide which ME quality setting to use */
+    x->me_flags = 0;
+    switch( avctx->me_method ) {
+       case ME_FULL:   /* Quality 6 */
+           x->me_flags |=  XVID_ME_EXTSEARCH16
+                       |   XVID_ME_EXTSEARCH8;
+
+       case ME_EPZS:   /* Quality 4 */
+           x->me_flags |=  XVID_ME_ADVANCEDDIAMOND8
+                       |   XVID_ME_HALFPELREFINE8
+                       |   XVID_ME_CHROMA_PVOP
+                       |   XVID_ME_CHROMA_BVOP;
+
+       case ME_LOG:    /* Quality 2 */
+       case ME_PHODS:
+       case ME_X1:
+           x->me_flags |=  XVID_ME_ADVANCEDDIAMOND16
+                       |   XVID_ME_HALFPELREFINE16;
+
+       case ME_ZERO:   /* Quality 0 */
+       default:
+           break;
+    }
+
+    /* Decide how we should decide blocks */
+    switch( avctx->mb_decision ) {
+       case 2:
+           x->vop_flags |= XVID_VOP_MODEDECISION_RD;
+           x->me_flags |=  XVID_ME_HALFPELREFINE8_RD
+                       |   XVID_ME_QUARTERPELREFINE8_RD
+                       |   XVID_ME_EXTSEARCH_RD
+                       |   XVID_ME_CHECKPREDICTION_RD;
+       case 1:
+           if( !(x->vop_flags & XVID_VOP_MODEDECISION_RD) )
+               x->vop_flags |= XVID_VOP_FAST_MODEDECISION_RD;
+           x->me_flags |=  XVID_ME_HALFPELREFINE16_RD
+                       |   XVID_ME_QUARTERPELREFINE16_RD;
+
+       default:
+           break;
+    }
+
+    /* Bring in VOL flags from ffmpeg command-line */
+    x->vol_flags = 0;
+    if( xvid_flags & CODEC_FLAG_GMC ) {
+        x->vol_flags |= XVID_VOL_GMC;
+        x->me_flags |= XVID_ME_GME_REFINE;
+    }
+    if( xvid_flags & CODEC_FLAG_QPEL ) {
+        x->vol_flags |= XVID_VOL_QUARTERPEL;
+        x->me_flags |= XVID_ME_QUARTERPELREFINE16;
+        if( x->vop_flags & XVID_VOP_INTER4V )
+            x->me_flags |= XVID_ME_QUARTERPELREFINE8;
+    }
+
+    memset(&xvid_gbl_init, 0, sizeof(xvid_gbl_init));
+    xvid_gbl_init.version = XVID_VERSION;
+    xvid_gbl_init.debug = 0;
+
+#ifdef ARCH_POWERPC
+    /* XviD's PPC support is borked, use libavcodec to detect */
+#if HAVE_ALTIVEC==1
+    if( has_altivec() ) {
+        xvid_gbl_init.cpu_flags = XVID_CPU_FORCE | XVID_CPU_ALTIVEC;
+    } else
+#endif
+        xvid_gbl_init.cpu_flags = XVID_CPU_FORCE;
+#else
+    /* XviD can detect on x86 */
+    xvid_gbl_init.cpu_flags = 0;
+#endif
+
+    /* Initialize */
+    xvid_global(NULL, XVID_GBL_INIT, &xvid_gbl_init, NULL);
+
+    /* Create the encoder reference */
+    memset(&xvid_enc_create, 0, sizeof(xvid_enc_create));
+    xvid_enc_create.version = XVID_VERSION;
+
+    /* Store the desired frame size */
+    xvid_enc_create.width = x->xsize = avctx->width;
+    xvid_enc_create.height = x->ysize = avctx->height;
+
+    /* XviD can determine the proper profile to use */
+    /* xvid_enc_create.profile = XVID_PROFILE_S_L3; */
+
+    /* We don't use zones or threads */
+    xvid_enc_create.zones = NULL;
+    xvid_enc_create.num_zones = 0;
+    xvid_enc_create.num_threads = 0;
+
+    xvid_enc_create.plugins = plugins;
+    xvid_enc_create.num_plugins = 0;
+
+    /* Initialize Buffers */
+    x->twopassbuffer = NULL;
+    x->old_twopassbuffer = NULL;
+    x->twopassfile = NULL;
+
+    if( xvid_flags & CODEC_FLAG_PASS1 ) {
+        memset(&rc2pass1, 0, sizeof(xvid_ff_pass1_t));
+        rc2pass1.version = XVID_VERSION;
+        rc2pass1.context = x;
+        x->twopassbuffer = av_malloc(BUFFER_SIZE);
+        x->old_twopassbuffer = av_malloc(BUFFER_SIZE);
+        if( x->twopassbuffer == NULL || x->old_twopassbuffer == NULL ) {
+            av_log(avctx, AV_LOG_ERROR,
+                "XviD: Cannot allocate 2-pass log buffers\n");
+            return -1;
+        }
+        x->twopassbuffer[0] = x->old_twopassbuffer[0] = 0;
+
+        plugins[xvid_enc_create.num_plugins].func = xvid_ff_2pass;
+        plugins[xvid_enc_create.num_plugins].param = &rc2pass1;
+        xvid_enc_create.num_plugins++;
+    } else if( xvid_flags & CODEC_FLAG_PASS2 ) {
+        memset(&rc2pass2, 0, sizeof(xvid_plugin_2pass2_t));
+        rc2pass2.version = XVID_VERSION;
+        rc2pass2.bitrate = avctx->bit_rate;
+
+        fd = av_tempfile("xvidff.", &(x->twopassfile));
+        if( fd == -1 ) {
+            av_log(avctx, AV_LOG_ERROR,
+                "XviD: Cannot write 2-pass pipe\n");
+            return -1;
+        }
+
+        if( avctx->stats_in == NULL ) {
+            av_log(avctx, AV_LOG_ERROR,
+                "XviD: No 2-pass information loaded for second pass\n");
+            return -1;
+        }
+
+        if( strlen(avctx->stats_in) >
+              write(fd, avctx->stats_in, strlen(avctx->stats_in)) ) {
+            close(fd);
+            av_log(avctx, AV_LOG_ERROR,
+                "XviD: Cannot write to 2-pass pipe\n");
+            return -1;
+        }
+
+        close(fd);
+        rc2pass2.filename = x->twopassfile;
+        plugins[xvid_enc_create.num_plugins].func = xvid_plugin_2pass2;
+        plugins[xvid_enc_create.num_plugins].param = &rc2pass2;
+        xvid_enc_create.num_plugins++;
+    } else if( !(xvid_flags & CODEC_FLAG_QSCALE) ) {
+        /* Single Pass Bitrate Control! */
+        memset(&single, 0, sizeof(xvid_plugin_single_t));
+        single.version = XVID_VERSION;
+        single.bitrate = avctx->bit_rate;
+
+        plugins[xvid_enc_create.num_plugins].func = xvid_plugin_single;
+        plugins[xvid_enc_create.num_plugins].param = &single;
+        xvid_enc_create.num_plugins++;
+    }
+
+    /* Luminance Masking */
+    if( 0.0 != avctx->lumi_masking ) {
+        plugins[xvid_enc_create.num_plugins].func = xvid_plugin_lumimasking;
+        plugins[xvid_enc_create.num_plugins].param = NULL;
+        xvid_enc_create.num_plugins++;
+    }
+
+    /* Frame Rate and Key Frames */
+    xvid_correct_framerate(avctx);
+    xvid_enc_create.fincr = avctx->time_base.num;
+    xvid_enc_create.fbase = avctx->time_base.den;
+    if( avctx->gop_size > 0 )
+        xvid_enc_create.max_key_interval = avctx->gop_size;
+    else
+        xvid_enc_create.max_key_interval = 240; /* XviD's best default */
+
+    /* Quants */
+    if( xvid_flags & CODEC_FLAG_QSCALE ) x->qscale = 1;
+    else x->qscale = 0;
+
+    xvid_enc_create.min_quant[0] = avctx->qmin;
+    xvid_enc_create.min_quant[1] = avctx->qmin;
+    xvid_enc_create.min_quant[2] = avctx->qmin;
+    xvid_enc_create.max_quant[0] = avctx->qmax;
+    xvid_enc_create.max_quant[1] = avctx->qmax;
+    xvid_enc_create.max_quant[2] = avctx->qmax;
+
+    /* Quant Matrices */
+    x->intra_matrix = x->inter_matrix = NULL;
+    if( avctx->mpeg_quant )
+       x->vol_flags |= XVID_VOL_MPEGQUANT;
+    if( (avctx->intra_matrix || avctx->inter_matrix) ) {
+       x->vol_flags |= XVID_VOL_MPEGQUANT;
+
+       if( avctx->intra_matrix ) {
+           intra = avctx->intra_matrix;
+           x->intra_matrix = av_malloc(sizeof(unsigned char) * 64);
+       } else
+           intra = NULL;
+       if( avctx->inter_matrix ) {
+           inter = avctx->inter_matrix;
+           x->inter_matrix = av_malloc(sizeof(unsigned char) * 64);
+       } else
+           inter = NULL;
+
+       for( i = 0; i < 64; i++ ) {
+           if( intra )
+               x->intra_matrix[i] = (unsigned char)intra[i];
+           if( inter )
+               x->inter_matrix[i] = (unsigned char)inter[i];
+       }
+    }
+
+    /* Misc Settings */
+    xvid_enc_create.frame_drop_ratio = 0;
+    xvid_enc_create.global = 0;
+    if( xvid_flags & CODEC_FLAG_CLOSED_GOP )
+        xvid_enc_create.global |= XVID_GLOBAL_CLOSED_GOP;
+
+    /* Determines which codec mode we are operating in */
+    avctx->extradata = NULL;
+    avctx->extradata_size = 0;
+    if( xvid_flags & CODEC_FLAG_GLOBAL_HEADER ) {
+        /* In this case, we are claiming to be MPEG4 */
+        x->quicktime_format = 1;
+        avctx->codec_id = CODEC_ID_MPEG4;
+    } else {
+        /* We are claiming to be XviD */
+        x->quicktime_format = 0;
+        if(!avctx->codec_tag)
+            avctx->codec_tag = ff_get_fourcc("xvid");
+    }
+
+    /* Bframes */
+    xvid_enc_create.max_bframes = avctx->max_b_frames;
+    xvid_enc_create.bquant_offset = 100 * avctx->b_quant_offset;
+    xvid_enc_create.bquant_ratio = 100 * avctx->b_quant_factor;
+    if( avctx->max_b_frames > 0  && !x->quicktime_format ) xvid_enc_create.global |= XVID_GLOBAL_PACKED;
+
+    /* Create encoder context */
+    xerr = xvid_encore(NULL, XVID_ENC_CREATE, &xvid_enc_create, NULL);
+    if( xerr ) {
+        av_log(avctx, AV_LOG_ERROR, "XviD: Could not create encoder reference\n");
+        return -1;
+    }
+
+    x->encoder_handle = xvid_enc_create.handle;
+    avctx->coded_frame = &x->encoded_picture;
+
+    return 0;
+}
+
+/**
+ * Encodes a single frame.
+ *
+ * @param avctx AVCodecContext pointer to context
+ * @param frame Pointer to encoded frame buffer
+ * @param buf_size Size of encoded frame buffer
+ * @param data Pointer to AVFrame of unencoded frame
+ * @return Returns 0 on success, -1 on failure
+ */
+int ff_xvid_encode_frame(AVCodecContext *avctx,
+                         unsigned char *frame, int buf_size, void *data) {
+    int xerr, i;
+    char *tmp;
+    xvid_context_t *x = avctx->priv_data;
+    AVFrame *picture = data;
+    AVFrame *p = &(x->encoded_picture);
+
+    xvid_enc_frame_t xvid_enc_frame;
+    xvid_enc_stats_t xvid_enc_stats;
+
+    /* Start setting up the frame */
+    memset(&xvid_enc_frame, 0, sizeof(xvid_enc_frame));
+    xvid_enc_frame.version = XVID_VERSION;
+    memset(&xvid_enc_stats, 0, sizeof(xvid_enc_stats));
+    xvid_enc_stats.version = XVID_VERSION;
+    *p = *picture;
+
+    /* Let XviD know where to put the frame. */
+    xvid_enc_frame.bitstream = frame;
+    xvid_enc_frame.length = buf_size;
+
+    /* Initialize input image fields */
+    if( avctx->pix_fmt != PIX_FMT_YUV420P ) {
+        av_log(avctx, AV_LOG_ERROR, "XviD: Color spaces other than 420p not supported\n");
+        return -1;
+    }
+
+    xvid_enc_frame.input.csp = XVID_CSP_PLANAR; /* YUV420P */
+
+    for( i = 0; i < 4; i++ ) {
+        xvid_enc_frame.input.plane[i] = picture->data[i];
+        xvid_enc_frame.input.stride[i] = picture->linesize[i];
+    }
+
+    /* Encoder Flags */
+    xvid_enc_frame.vop_flags = x->vop_flags;
+    xvid_enc_frame.vol_flags = x->vol_flags;
+    xvid_enc_frame.motion = x->me_flags;
+    xvid_enc_frame.type = XVID_TYPE_AUTO;
+
+    /* Quant Setting */
+    if( x->qscale ) xvid_enc_frame.quant = picture->quality / FF_QP2LAMBDA;
+    else xvid_enc_frame.quant = 0;
+
+    /* Matrices */
+    xvid_enc_frame.quant_intra_matrix = x->intra_matrix;
+    xvid_enc_frame.quant_inter_matrix = x->inter_matrix;
+
+    /* Encode */
+    xerr = xvid_encore(x->encoder_handle, XVID_ENC_ENCODE,
+        &xvid_enc_frame, &xvid_enc_stats);
+
+    /* Two-pass log buffer swapping */
+    avctx->stats_out = NULL;
+    if( x->twopassbuffer ) {
+        tmp = x->old_twopassbuffer;
+        x->old_twopassbuffer = x->twopassbuffer;
+        x->twopassbuffer = tmp;
+        x->twopassbuffer[0] = 0;
+        if( x->old_twopassbuffer[0] != 0 ) {
+            avctx->stats_out = x->old_twopassbuffer;
+        }
+    }
+
+    if( 0 <= xerr ) {
+        p->quality = xvid_enc_stats.quant * FF_QP2LAMBDA;
+        if( xvid_enc_stats.type == XVID_TYPE_PVOP )
+            p->pict_type = FF_P_TYPE;
+        else if( xvid_enc_stats.type == XVID_TYPE_BVOP )
+            p->pict_type = FF_B_TYPE;
+        else if( xvid_enc_stats.type == XVID_TYPE_SVOP )
+            p->pict_type = FF_S_TYPE;
+        else
+            p->pict_type = FF_I_TYPE;
+        if( xvid_enc_frame.out_flags & XVID_KEYFRAME ) {
+            p->key_frame = 1;
+            if( x->quicktime_format )
+                return xvid_strip_vol_header(avctx, frame,
+                    xvid_enc_stats.hlength, xerr);
+         } else
+            p->key_frame = 0;
+
+        return xerr;
+    } else {
+        av_log(avctx, AV_LOG_ERROR, "XviD: Encoding Error Occurred: %i\n", xerr);
+        return -1;
+    }
+}
+
+/**
+ * Destroys the private context for the encoder.
+ * All buffers are freed, and the XviD encoder context is destroyed.
+ *
+ * @param avctx AVCodecContext pointer to context
+ * @return Returns 0, success guaranteed
+ */
+int ff_xvid_encode_close(AVCodecContext *avctx) {
+    xvid_context_t *x = avctx->priv_data;
+
+    xvid_encore(x->encoder_handle, XVID_ENC_DESTROY, NULL, NULL);
+
+    if( avctx->extradata != NULL )
+        av_free(avctx->extradata);
+    if( x->twopassbuffer != NULL ) {
+        av_free(x->twopassbuffer);
+        av_free(x->old_twopassbuffer);
+    }
+    if( x->twopassfile != NULL )
+        av_free(x->twopassfile);
+    if( x->intra_matrix != NULL )
+        av_free(x->intra_matrix);
+    if( x->inter_matrix != NULL )
+        av_free(x->inter_matrix);
+
+    return 0;
+}
+
+/**
+ * Routine to create a global VO/VOL header for MP4 container.
+ * What we do here is extract the header from the XviD bitstream
+ * as it is encoded. We also strip the repeated headers from the
+ * bitstream when a global header is requested for MPEG-4 ISO
+ * compliance.
+ *
+ * @param avctx AVCodecContext pointer to context
+ * @param frame Pointer to encoded frame data
+ * @param header_len Length of header to search
+ * @param frame_len Length of encoded frame data
+ * @return Returns new length of frame data
+ */
+int xvid_strip_vol_header(AVCodecContext *avctx,
+                  unsigned char *frame,
+                  unsigned int header_len,
+                  unsigned int frame_len) {
+    int vo_len = 0, i;
+
+    for( i = 0; i < header_len - 3; i++ ) {
+        if( frame[i] == 0x00 &&
+            frame[i+1] == 0x00 &&
+            frame[i+2] == 0x01 &&
+            frame[i+3] == 0xB6 ) {
+            vo_len = i;
+            break;
+        }
+    }
+
+    if( vo_len > 0 ) {
+        /* We need to store the header, so extract it */
+        if( avctx->extradata == NULL ) {
+            avctx->extradata = av_malloc(vo_len);
+            memcpy(avctx->extradata, frame, vo_len);
+            avctx->extradata_size = vo_len;
+        }
+        /* Less dangerous now, memmove properly copies the two
+           chunks of overlapping data */
+        memmove(frame, &(frame[vo_len]), frame_len - vo_len);
+        return frame_len - vo_len;
+    } else
+        return frame_len;
+}
+
+/**
+ * Routine to correct a possibly erroneous framerate being fed to us.
+ * XviD currently chokes on framerates where the ticks per frame is
+ * extremely large. This function works to correct problems in this area
+ * by estimating a new framerate and taking the simpler fraction of
+ * the two presented.
+ *
+ * @param avctx Context that contains the framerate to correct.
+ */
+void xvid_correct_framerate(AVCodecContext *avctx) {
+    int frate, fbase;
+    int est_frate, est_fbase;
+    int gcd;
+    float est_fps, fps;
+
+    frate = avctx->time_base.den;
+    fbase = avctx->time_base.num;
+
+    gcd = ff_gcd(frate, fbase);
+    if( gcd > 1 ) {
+        frate /= gcd;
+        fbase /= gcd;
+    }
+
+    if( frate <= 65000 && fbase <= 65000 ) {
+        avctx->time_base.den = frate;
+        avctx->time_base.num = fbase;
+        return;
+    }
+
+    fps = (float)frate / (float)fbase;
+    est_fps = roundf(fps * 1000.0) / 1000.0;
+
+    est_frate = (int)est_fps;
+    if( est_fps > (int)est_fps ) {
+        est_frate = (est_frate + 1) * 1000;
+        est_fbase = (int)roundf((float)est_frate / est_fps);
+    } else
+        est_fbase = 1;
+
+    gcd = ff_gcd(est_frate, est_fbase);
+    if( gcd > 1 ) {
+        est_frate /= gcd;
+        est_fbase /= gcd;
+    }
+
+    if( fbase > est_fbase ) {
+        avctx->time_base.den = est_frate;
+        avctx->time_base.num = est_fbase;
+        av_log(avctx, AV_LOG_DEBUG,
+            "XviD: framerate re-estimated: %.2f, %.3f%% correction\n",
+            est_fps, (((est_fps - fps)/fps) * 100.0));
+    } else {
+        avctx->time_base.den = frate;
+        avctx->time_base.num = fbase;
+    }
+}
+
+/*
+ * XviD 2-Pass Kludge Section
+ *
+ * XviD's default 2-pass doesn't allow us to create data as we need to, so
+ * this section spends time replacing the first pass plugin so we can write
+ * statistic information as libavcodec requests in. We have another kludge
+ * that allows us to pass data to the second pass in XviD without a custom
+ * rate-control plugin.
+ */
+
+/**
+ * Initializes the two-pass plugin and context.
+ *
+ * @param param Input construction parameter structure
+ * @param handle Private context handle
+ * @return Returns XVID_ERR_xxxx on failure, or 0 on success.
+ */
+static int xvid_ff_2pass_create(xvid_plg_create_t * param,
+                                void ** handle) {
+    xvid_ff_pass1_t *x = (xvid_ff_pass1_t *)param->param;
+    char *log = x->context->twopassbuffer;
+
+    /* Do a quick bounds check */
+    if( log == NULL )
+        return XVID_ERR_FAIL;
+
+    /* We use snprintf() */
+    /* This is because we can safely prevent a buffer overflow */
+    log[0] = 0;
+    snprintf(log, BUFFER_REMAINING(log),
+        "# ffmpeg 2-pass log file, using xvid codec\n");
+    snprintf(BUFFER_CAT(log), BUFFER_REMAINING(log),
+        "# Do not modify. libxvidcore version: %d.%d.%d\n\n",
+        XVID_VERSION_MAJOR(XVID_VERSION),
+        XVID_VERSION_MINOR(XVID_VERSION),
+        XVID_VERSION_PATCH(XVID_VERSION));
+
+    *handle = x->context;
+    return 0;
+}
+
+/**
+ * Destroys the two-pass plugin context.
+ *
+ * @param ref Context pointer for the plugin
+ * @param param Destrooy context
+ * @return Returns 0, success guaranteed
+ */
+static int xvid_ff_2pass_destroy(xvid_context_t *ref,
+                                xvid_plg_destroy_t *param) {
+    /* Currently cannot think of anything to do on destruction */
+    /* Still, the framework should be here for reference/use */
+    if( ref->twopassbuffer != NULL )
+        ref->twopassbuffer[0] = 0;
+    return 0;
+}
+
+/**
+ * Enables fast encode mode during the first pass.
+ *
+ * @param ref Context pointer for the plugin
+ * @param param Frame data
+ * @return Returns 0, success guaranteed
+ */
+static int xvid_ff_2pass_before(xvid_context_t *ref,
+                                xvid_plg_data_t *param) {
+    int motion_remove;
+    int motion_replacements;
+    int vop_remove;
+
+    /* Nothing to do here, result is changed too much */
+    if( param->zone && param->zone->mode == XVID_ZONE_QUANT )
+        return 0;
+
+    /* We can implement a 'turbo' first pass mode here */
+    param->quant = 2;
+
+    /* Init values */
+    motion_remove = ~XVID_ME_CHROMA_PVOP &
+                    ~XVID_ME_CHROMA_BVOP &
+                    ~XVID_ME_EXTSEARCH16 &
+                    ~XVID_ME_ADVANCEDDIAMOND16;
+    motion_replacements = XVID_ME_FAST_MODEINTERPOLATE |
+                          XVID_ME_SKIP_DELTASEARCH |
+                          XVID_ME_FASTREFINE16 |
+                          XVID_ME_BFRAME_EARLYSTOP;
+    vop_remove = ~XVID_VOP_MODEDECISION_RD &
+                 ~XVID_VOP_FAST_MODEDECISION_RD &
+                 ~XVID_VOP_TRELLISQUANT &
+                 ~XVID_VOP_INTER4V &
+                 ~XVID_VOP_HQACPRED;
+
+    param->vol_flags &= ~XVID_VOL_GMC;
+    param->vop_flags &= vop_remove;
+    param->motion_flags &= motion_remove;
+    param->motion_flags |= motion_replacements;
+
+    return 0;
+}
+
+/**
+ * Captures statistic data and writes it during first pass.
+ *
+ * @param ref Context pointer for the plugin
+ * @param param Statistic data
+ * @return Returns XVID_ERR_xxxx on failure, or 0 on success
+ */
+static int xvid_ff_2pass_after(xvid_context_t *ref,
+                                xvid_plg_data_t *param) {
+    char *log = ref->twopassbuffer;
+    char *frame_types = " ipbs";
+    char frame_type;
+
+    /* Quick bounds check */
+    if( log == NULL )
+        return XVID_ERR_FAIL;
+
+    /* Convert the type given to us into a character */
+    if( param->type < 5 && param->type > 0 ) {
+        frame_type = frame_types[param->type];
+    } else {
+        return XVID_ERR_FAIL;
+    }
+
+    snprintf(BUFFER_CAT(log), BUFFER_REMAINING(log),
+        "%c %d %d %d %d %d %d\n",
+        frame_type, param->stats.quant, param->stats.kblks, param->stats.mblks,
+        param->stats.ublks, param->stats.length, param->stats.hlength);
+
+    return 0;
+}
+
+/**
+ * Dispatch function for our custom plugin.
+ * This handles the dispatch for the XviD plugin. It passes data
+ * on to other functions for actual processing.
+ *
+ * @param ref Context pointer for the plugin
+ * @param cmd The task given for us to complete
+ * @param p1 First parameter (varies)
+ * @param p2 Second parameter (varies)
+ * @return Returns XVID_ERR_xxxx on failure, or 0 on success
+ */
+int xvid_ff_2pass(void *ref, int cmd, void *p1, void *p2) {
+    switch( cmd ) {
+        case XVID_PLG_INFO:
+        case XVID_PLG_FRAME:
+            return 0;
+
+        case XVID_PLG_BEFORE:
+            return xvid_ff_2pass_before(ref, p1);
+
+        case XVID_PLG_CREATE:
+            return xvid_ff_2pass_create(p1, p2);
+
+        case XVID_PLG_AFTER:
+            return xvid_ff_2pass_after(ref, p1);
+
+        case XVID_PLG_DESTROY:
+            return xvid_ff_2pass_destroy(ref, p1);
+
+        default:
+            return XVID_ERR_FAIL;
+    }
+}
+
+/**
+ * XviD codec definition for libavcodec.
+ */
+AVCodec xvid_encoder = {
+    "xvid",
+    CODEC_TYPE_VIDEO,
+    CODEC_ID_XVID,
+    sizeof(xvid_context_t),
+    ff_xvid_encode_init,
+    ff_xvid_encode_frame,
+    ff_xvid_encode_close,
+    .pix_fmts= (enum PixelFormat[]){PIX_FMT_YUV420P, -1},
+};