[FFmpeg-devel] [PATCH] Adding Cinepak encoder (attached)

u-owvm at aetey.se u-owvm at aetey.se
Mon Jan 13 11:19:14 CET 2014


Hello,

This is the Cinepac encoder with the tweak allowing windows players to
handle the resulting files: the number of strips per frame is restricted
to below 3 which in my limited testing allowed playing by all of
the following:

- mplayer on Linux with the binary (windows dll) decoder
- windows media player on Windows XP
- windows media player on Windows 98
- windows media player on Windows 3.1

Raising the number of strips to 4 makes these programs crash immediately.

The former max strip number (the actual number is dynamically chosen
by the encoder) was 32, which allows for better quality, especially on
higher resolutions, and is accepted by the decoder in ffmpeg.

Now it is hardcoded to 3.

The files in my test did not play properly under Quicktime on MacOSX.
It seems that the description of the format (multimedia.cx wiki) is
insufficient/inconsistent with the assumptions of the Quicktime decoder.

The 3 strip limit seems to be present in Quicktime as well, up to 3
strips produce a distorted image while 4 strips make the player show
nothing at all.

Regards,
Rl
-------------- next part --------------
>From 136e7f823302c8da0dc707fc824b3df0d90f08fb Mon Sep 17 00:00:00 2001
From: Rl <addr-see-the-website at aetey.se>
Date: Sun, 12 Jan 2014 15:25:51 +0100
Subject: [PATCH 1/2] Adding Cinepak encoder.

Max number of strips/frame is set to 3
for compatibility with vintage players.
---
 MAINTAINERS             |    1 +
 libavcodec/Makefile     |    1 +
 libavcodec/allcodecs.c  |    2 +-
 libavcodec/cinepakenc.c | 1213 +++++++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 1216 insertions(+), 1 deletions(-)
 create mode 100644 libavcodec/cinepakenc.c

diff --git a/MAINTAINERS b/MAINTAINERS
index ebfb735..89ccade 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -148,6 +148,7 @@ Codecs:
   cdxl.c                                Paul B Mahol
   celp_filters.*                        Vitor Sessak
   cinepak.c                             Roberto Togni
+  cinepakenc.c                          Rl / Aetey G.T. AB
   cljr                                  Alex Beregszaszi
   cllc.c                                Derek Buitenhuis
   cook.c, cookdata.h                    Benjamin Larsson
diff --git a/libavcodec/Makefile b/libavcodec/Makefile
index c3f4114..2cb433e 100644
--- a/libavcodec/Makefile
+++ b/libavcodec/Makefile
@@ -152,6 +152,7 @@ OBJS-$(CONFIG_CAVS_DECODER)            += cavs.o cavsdec.o cavsdsp.o \
                                           cavsdata.o mpeg12data.o
 OBJS-$(CONFIG_CDGRAPHICS_DECODER)      += cdgraphics.o
 OBJS-$(CONFIG_CDXL_DECODER)            += cdxl.o
+OBJS-$(CONFIG_CINEPAK_ENCODER)         += cinepakenc.o
 OBJS-$(CONFIG_CINEPAK_DECODER)         += cinepak.o
 OBJS-$(CONFIG_CLJR_DECODER)            += cljr.o
 OBJS-$(CONFIG_CLJR_ENCODER)            += cljr.o
diff --git a/libavcodec/allcodecs.c b/libavcodec/allcodecs.c
index cacc81f..9ddb0f9 100644
--- a/libavcodec/allcodecs.c
+++ b/libavcodec/allcodecs.c
@@ -122,7 +122,7 @@ void avcodec_register_all(void)
     REGISTER_DECODER(CAVS,              cavs);
     REGISTER_DECODER(CDGRAPHICS,        cdgraphics);
     REGISTER_DECODER(CDXL,              cdxl);
-    REGISTER_DECODER(CINEPAK,           cinepak);
+    REGISTER_ENCDEC (CINEPAK,           cinepak);
     REGISTER_ENCDEC (CLJR,              cljr);
     REGISTER_DECODER(CLLC,              cllc);
     REGISTER_ENCDEC (COMFORTNOISE,      comfortnoise);
diff --git a/libavcodec/cinepakenc.c b/libavcodec/cinepakenc.c
new file mode 100644
index 0000000..8356d36
--- /dev/null
+++ b/libavcodec/cinepakenc.c
@@ -0,0 +1,1213 @@
+/*
+ * Cinepak encoder (c) 2011 Tomas H?rdin
+ * http://titan.codemill.se/~tomhar/cinepakenc.patch
+ *
+ * fixes and improvements (c) 2013, 2014 Rl, Aetey Global Technologies AB
+ *
+
+Permission is hereby granted, free of charge, to any person obtaining a
+copy of this software and associated documentation files (the "Software"),
+to deal in the Software without restriction, including without limitation
+the rights to use, copy, modify, merge, publish, distribute, sublicense,
+and/or sell copies of the Software, and to permit persons to whom the
+Software is furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included
+in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
+OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
+ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+OTHER DEALINGS IN THE SOFTWARE.
+
+ * TODO:
+ * - optimize: color space conversion, ...
+ * - implement options to set the min/max number of strips?
+ * MAYBE:
+ * - "optimally" split the frame into several non-regular areas
+ *   using a separate codebook pair for each area and approximating
+ *   the area by several rectangular strips (generally not full width ones)
+ *   (use quadtree splitting? a simple fixed-granularity grid?)
+ *
+ *
+ * version 2014-01-12 Rl
+ * - making the encoder compatible with vintage decoders
+ *   and adding some yet unused code for possible future
+ *   incremental codebook updates
+ *
+ * version 2013-04-28 Rl
+ * - bugfixed codebook optimization logic
+ *
+ * version 2013-02-14 Rl
+ * "Valentine's Day" version:
+ * - made strip division more robust
+ * - minimized bruteforcing the number of strips,
+ *   (costs some R/D but speeds up compession a lot), the heuristic
+ *   assumption is that score as a function of the number of strips has
+ *   one wide minimum which moves slowly, of course not fully true
+ * - simplified codebook generation,
+ *   the old code was meant for other optimizations than we actually do
+ * - optimized the codebook generation / error estimation for MODE_MC
+ *
+ * version 2013-02-12 Rl
+ * - separated codebook training sets, avoided the transfer of wasted bytes,
+ *   which yields both better quality and smaller files
+ * - now using the correct colorspace (TODO: move conversion to libswscale)
+ *
+ * version 2013-02-08 Rl
+ * - fixes/optimization in multistrip encoding and codebook size choice,
+ *   quality/bitrate is now better than that of the binary proprietary encoder
+ */
+
+#include "libavutil/intreadwrite.h"
+#include "avcodec.h"
+#include "libavutil/lfg.h"
+#include "elbg.h"
+#include "internal.h"
+
+#include <assert.h>
+
+#define CVID_HEADER_SIZE 10
+#define STRIP_HEADER_SIZE 12
+#define CHUNK_HEADER_SIZE 4
+
+#define MB_SIZE 4           //4x4 MBs
+#define MB_AREA (MB_SIZE*MB_SIZE)
+
+#define VECTOR_MAX 6        //six or four entries per vector depending on format
+#define CODEBOOK_MAX 256    //size of a codebook
+
+//#define MAX_STRIPS  32      //Note: having fewer choices regarding the number of strips speeds up encoding (obviously)
+#define MAX_STRIPS  3       // This seems to be max for vintage players! -- rl
+// TODO: we should have a "vintage compatibilty" switch
+#define MIN_STRIPS  1       //Note: having more strips speeds up encoding the frame (this is less obvious)
+// MAX_STRIPS limits the maximum quality you can reach
+//            when you want hight quality on high resolutions,
+// MIN_STRIPS limits the minimum efficiently encodable bit rate
+//            on low resolutions
+// the numbers are only used for brute force optimization for the first frame,
+// for the following frames they are adaptively readjusted
+// NOTE the decoder in ffmpeg has its own (arbitrary?) limitation on the number
+// of strips, currently 32
+
+typedef enum {
+    MODE_V1_ONLY = 0,
+    MODE_V1_V4,
+    MODE_MC,
+
+    MODE_COUNT,
+} CinepakMode;
+
+typedef enum {
+    ENC_V1,
+    ENC_V4,
+    ENC_SKIP,
+
+    ENC_UNCERTAIN
+} mb_encoding;
+
+typedef struct {
+    int v1_vector;                  //index into v1 codebook
+    int v1_error;                   //error when using V1 encoding
+    int v4_vector[4];               //indices into v4 codebooks
+    int v4_error;                   //error when using V4 encoding
+    int skip_error;                 //error when block is skipped (aka copied from last frame)
+    mb_encoding best_encoding;      //last result from calculate_mode_score()
+} mb_info;
+
+typedef struct {
+    int v1_codebook[CODEBOOK_MAX*VECTOR_MAX];
+    int v4_codebook[CODEBOOK_MAX*VECTOR_MAX];
+    int v1_size;
+    int v4_size;
+    CinepakMode mode;
+} strip_info;
+
+typedef struct {
+    AVCodecContext *avctx;
+    unsigned char *pict_bufs[4], *strip_buf, *frame_buf;
+    AVFrame last_frame;
+    AVFrame best_frame;
+    AVFrame scratch_frame;
+    AVFrame input_frame;
+    enum AVPixelFormat pix_fmt;
+    int w, h;
+    int frame_buf_size;
+    int curframe, keyint;
+    AVLFG randctx;
+    uint64_t lambda;
+    int *codebook_input;
+    int *codebook_closest;
+    mb_info *mb;                                //MB RD state
+    int min_strips;          //the current limit
+    int max_strips;          //the current limit
+#ifdef CINEPAKENC_DEBUG
+    mb_info *best_mb;                           //TODO: remove. only used for printing stats
+    int num_v1_mode, num_v4_mode, num_mc_mode;
+    int num_v1_encs, num_v4_encs, num_skips;
+#endif
+} CinepakEncContext;
+
+static av_cold int cinepak_encode_init(AVCodecContext *avctx)
+{
+    CinepakEncContext *s = avctx->priv_data;
+    int x, mb_count, strip_buf_size, frame_buf_size;
+    
+    if (avctx->width & 3 || avctx->height & 3) {
+        av_log(avctx, AV_LOG_ERROR, "width and height must be multiples of four (got %ix%i)\n",
+                avctx->width, avctx->height);
+        return AVERROR(EINVAL);
+    }
+
+    if (!(s->codebook_input = av_malloc(sizeof(int) * (avctx->pix_fmt == AV_PIX_FMT_RGB24 ? 6 : 4) * (avctx->width * avctx->height) >> 2)))
+        return AVERROR(ENOMEM);
+
+    if (!(s->codebook_closest = av_malloc(sizeof(int) * (avctx->width * avctx->height) >> 2)))
+        goto enomem;
+
+    for(x = 0; x < (avctx->pix_fmt == AV_PIX_FMT_RGB24 ? 4 : 3); x++)
+        if(!(s->pict_bufs[x] = av_malloc((avctx->pix_fmt == AV_PIX_FMT_RGB24 ? 6 : 4) * (avctx->width * avctx->height) >> 2)))
+            goto enomem;
+
+    mb_count = avctx->width * avctx->height / MB_AREA;
+    
+    //the largest possible chunk is 0x31 with all MBs encoded in V4 mode
+    //and full codebooks being replaced in INTER mode,
+    // which is 34 bits per MB
+    //and 2*256 extra flag bits per strip
+    strip_buf_size = STRIP_HEADER_SIZE + 3 * CHUNK_HEADER_SIZE + 2 * VECTOR_MAX * CODEBOOK_MAX + 4 * (mb_count + (mb_count + 15) / 16) + (2 * CODEBOOK_MAX)/8;
+
+    frame_buf_size = CVID_HEADER_SIZE + MAX_STRIPS * strip_buf_size;
+
+    if (!(s->strip_buf = av_malloc(strip_buf_size)))
+        goto enomem;
+
+    if (!(s->frame_buf = av_malloc(frame_buf_size)))
+        goto enomem;
+
+    if (!(s->mb = av_malloc(mb_count*sizeof(mb_info))))
+        goto enomem;
+
+#ifdef CINEPAKENC_DEBUG
+    if (!(s->best_mb = av_malloc(mb_count*sizeof(mb_info))))
+        goto enomem;
+#endif
+
+    av_lfg_init(&s->randctx, 1);
+    s->avctx = avctx;
+    s->w = avctx->width;
+    s->h = avctx->height;
+    s->frame_buf_size = frame_buf_size;
+    s->curframe = 0;
+    s->keyint = avctx->keyint_min;
+    s->pix_fmt = avctx->pix_fmt;
+
+    //set up AVFrames
+    s->last_frame.data[0]        = s->pict_bufs[0];
+    s->last_frame.linesize[0]    = s->w;
+    s->best_frame.data[0]        = s->pict_bufs[1];
+    s->best_frame.linesize[0]    = s->w;
+    s->scratch_frame.data[0]     = s->pict_bufs[2];
+    s->scratch_frame.linesize[0] = s->w;
+
+    if(s->pix_fmt == AV_PIX_FMT_RGB24) {
+        s->last_frame.data[1]        = s->last_frame.data[0] + s->w * s->h;
+        s->last_frame.data[2]        = s->last_frame.data[1] + ((s->w * s->h) >> 2);
+        s->last_frame.linesize[1]    = s->last_frame.linesize[2] = s->w >> 1;
+
+        s->best_frame.data[1]        = s->best_frame.data[0] + s->w * s->h;
+        s->best_frame.data[2]        = s->best_frame.data[1] + ((s->w * s->h) >> 2);
+        s->best_frame.linesize[1]    = s->best_frame.linesize[2] = s->w >> 1;
+
+        s->scratch_frame.data[1]     = s->scratch_frame.data[0] + s->w * s->h;
+        s->scratch_frame.data[2]     = s->scratch_frame.data[1] + ((s->w * s->h) >> 2);
+        s->scratch_frame.linesize[1] = s->scratch_frame.linesize[2] = s->w >> 1;
+
+        s->input_frame.data[0]       = s->pict_bufs[3];
+        s->input_frame.linesize[0]   = s->w;
+        s->input_frame.data[1]       = s->input_frame.data[0] + s->w * s->h;
+        s->input_frame.data[2]       = s->input_frame.data[1] + ((s->w * s->h) >> 2);
+        s->input_frame.linesize[1]   = s->input_frame.linesize[2] = s->w >> 1;
+    }
+
+    s->min_strips = MIN_STRIPS;
+    s->max_strips = MAX_STRIPS;
+
+#ifdef CINEPAKENC_DEBUG
+    s->num_v1_mode = s->num_v4_mode = s->num_mc_mode = s->num_v1_encs = s->num_v4_encs = s->num_skips = 0;
+#endif
+
+    return 0;
+
+enomem:
+    av_free(s->codebook_input);
+    av_free(s->codebook_closest);
+    av_free(s->strip_buf);
+    av_free(s->frame_buf);
+    av_free(s->mb);
+#ifdef CINEPAKENC_DEBUG
+    av_free(s->best_mb);
+#endif
+
+    for(x = 0; x < (avctx->pix_fmt == AV_PIX_FMT_RGB24 ? 4 : 3); x++)
+        av_free(s->pict_bufs[x]);
+
+    return AVERROR(ENOMEM);
+}
+
+static int64_t calculate_mode_score(CinepakEncContext *s, int h, strip_info *info, int report_only
+#ifdef CINEPAK_REPORT_SERR
+, int64_t *serr
+#endif
+)
+{
+    //score = FF_LAMBDA_SCALE * error + lambda * bits
+    int x;
+    int entry_size = s->pix_fmt == AV_PIX_FMT_RGB24 ? 6 : 4;
+    int mb_count = s->w * h / MB_AREA;
+    mb_info *mb;
+    int64_t score1, score2, score3;
+    int64_t ret = s->lambda * ((info->v1_size ? CHUNK_HEADER_SIZE + info->v1_size * entry_size : 0) +
+                   (info->v4_size ? CHUNK_HEADER_SIZE + info->v4_size * entry_size : 0) +
+                   CHUNK_HEADER_SIZE) << 3;
+
+    //av_log(s->avctx, AV_LOG_INFO, "sizes %3i %3i -> %9lli score mb_count %i", info->v1_size, info->v4_size, (long long int)ret, mb_count);
+
+#ifdef CINEPAK_REPORT_SERR
+    *serr = 0;
+#endif
+
+    switch(info->mode) {
+    case MODE_V1_ONLY:
+        //one byte per MB
+        ret += s->lambda * 8 * mb_count;
+
+// while calculating we assume all blocks are ENC_V1
+        for(x = 0; x < mb_count; x++) {
+            mb = &s->mb[x];
+            ret += FF_LAMBDA_SCALE * mb->v1_error;
+#ifdef CINEPAK_REPORT_SERR
+            *serr += mb->v1_error;
+#endif
+            if(!report_only)
+                mb->best_encoding = ENC_V1;
+        }
+
+        break;
+    case MODE_V1_V4:
+        //9 or 33 bits per MB
+        if(report_only) {
+            for(x = 0; x < mb_count; x++) {
+                int score, mberr;
+                mb = &s->mb[x];
+                if(mb->best_encoding == ENC_V1)
+                    score = s->lambda * 9  + FF_LAMBDA_SCALE * (mberr=mb->v1_error);
+                else
+                    score = s->lambda * 33 + FF_LAMBDA_SCALE * (mberr=mb->v4_error);
+                ret += score;
+#ifdef CINEPAK_REPORT_SERR
+                *serr += mberr;
+#endif
+            }
+        } else { // find best mode per block
+            for(x = 0; x < mb_count; x++) {
+                mb = &s->mb[x];
+                score1 = s->lambda * 9  + FF_LAMBDA_SCALE * mb->v1_error;
+                score2 = s->lambda * 33 + FF_LAMBDA_SCALE * mb->v4_error;
+
+                if(score1 <= score2) {
+                    ret += score1;
+#ifdef CINEPAK_REPORT_SERR
+                    *serr += mb->v1_error;
+#endif
+                    mb->best_encoding = ENC_V1;
+                } else {
+                    ret += score2;
+#ifdef CINEPAK_REPORT_SERR
+                    *serr += mb->v4_error;
+#endif
+                    mb->best_encoding = ENC_V4;
+                }
+            }
+        }
+
+        break;
+    case MODE_MC:
+        //1, 10 or 34 bits per MB
+        if(report_only) {
+            for(x = 0; x < mb_count; x++) {
+                int score, mberr;
+                mb = &s->mb[x];
+                if(mb->best_encoding == ENC_SKIP)
+                    score = s->lambda * 1  + FF_LAMBDA_SCALE * (mberr=mb->skip_error);
+                else if(mb->best_encoding == ENC_V1)
+                    score = s->lambda * 10 + FF_LAMBDA_SCALE * (mberr=mb->v1_error);
+                else
+                    score = s->lambda * 34 + FF_LAMBDA_SCALE * (mberr=mb->v4_error);
+                ret += score;
+#ifdef CINEPAK_REPORT_SERR
+                *serr += mberr;
+#endif
+            }
+        } else { // find best mode per block
+            for(x = 0; x < mb_count; x++) {
+                mb = &s->mb[x];
+                score1 = s->lambda * 1  + FF_LAMBDA_SCALE * mb->skip_error;
+                score2 = s->lambda * 10 + FF_LAMBDA_SCALE * mb->v1_error;
+                score3 = s->lambda * 34 + FF_LAMBDA_SCALE * mb->v4_error;
+
+                if(score1 <= score2 && score1 <= score3) {
+                    ret += score1;
+#ifdef CINEPAK_REPORT_SERR
+                    *serr += mb->skip_error;
+#endif
+                    mb->best_encoding = ENC_SKIP;
+                } else if(score2 <= score3) {
+                    ret += score2;
+#ifdef CINEPAK_REPORT_SERR
+                    *serr += mb->v1_error;
+#endif
+                    mb->best_encoding = ENC_V1;
+                } else {
+                    ret += score3;
+#ifdef CINEPAK_REPORT_SERR
+                    *serr += mb->v4_error;
+#endif
+                    mb->best_encoding = ENC_V4;
+                }
+            }
+        }
+
+        break;
+    }
+
+    return ret;
+}
+
+static int write_chunk_header(unsigned char *buf, int chunk_type, int chunk_size)
+{
+    buf[0] = chunk_type;
+    AV_WB24(&buf[1], chunk_size + CHUNK_HEADER_SIZE);
+    return CHUNK_HEADER_SIZE;
+}
+
+static int encode_codebook(CinepakEncContext *s, int *codebook, int size, int chunk_type_yuv, int chunk_type_gray, unsigned char *buf)
+{
+    int x, y, ret, entry_size = s->pix_fmt == AV_PIX_FMT_RGB24 ? 6 : 4;
+    int incremental_codebook_replacement_mode = 0; // hardcoded here,
+                // the compiler should notice that this is a constant -- rl
+
+    ret = write_chunk_header(buf,
+          s->pix_fmt == AV_PIX_FMT_RGB24 ?
+           chunk_type_yuv+(incremental_codebook_replacement_mode?1:0) :
+           chunk_type_gray+(incremental_codebook_replacement_mode?1:0),
+          entry_size * size
+           + (incremental_codebook_replacement_mode?(size+31)/32*4:0) );
+
+// we do codebook encoding according to the "intra" mode
+// but we keep the "dead" code for reference in case we will want
+// to use incremental codebook updates (which actually would give us
+// "kind of" motion compensation, especially in 1 strip/frame case) -- rl
+// (of course, the code will be not useful as-is)
+    if(incremental_codebook_replacement_mode) {
+        int flags = 0;
+        int flagsind;
+        for(x = 0; x < size; x++) {
+            if(flags == 0) {
+                flagsind = ret;
+                ret += 4;
+                flags = 0x80000000;
+            } else
+                flags = ((flags>>1) | 0x80000000);
+            for(y = 0; y < entry_size; y++)
+                buf[ret++] = codebook[y + x*entry_size] ^ (y >= 4 ? 0x80 : 0);
+            if((flags&0xffffffff) == 0xffffffff) {
+                AV_WB32(&buf[flagsind], flags);
+                flags = 0;
+            }
+        }
+        if(flags)
+            AV_WB32(&buf[flagsind], flags);
+    } else
+        for(x = 0; x < size; x++)
+            for(y = 0; y < entry_size; y++)
+                buf[ret++] = codebook[y + x*entry_size] ^ (y >= 4 ? 0x80 : 0);
+
+    return ret;
+}
+
+//sets out to the sub picture starting at (x,y) in in
+static void get_sub_picture(CinepakEncContext *s, int x, int y, AVPicture *in, AVPicture *out)
+{
+    out->data[0] = in->data[0] + x + y * in->linesize[0];
+    out->linesize[0] = in->linesize[0];
+
+    if(s->pix_fmt == AV_PIX_FMT_RGB24) {
+        out->data[1] = in->data[1] + (x >> 1) + (y >> 1) * in->linesize[1];
+        out->linesize[1] = in->linesize[1];
+
+        out->data[2] = in->data[2] + (x >> 1) + (y >> 1) * in->linesize[2];
+        out->linesize[2] = in->linesize[2];
+    }
+}
+
+//decodes the V1 vector in mb into the 4x4 MB pointed to by sub_pict
+static void decode_v1_vector(CinepakEncContext *s, AVPicture *sub_pict, int v1_vector, strip_info *info)
+{
+    int entry_size = s->pix_fmt == AV_PIX_FMT_RGB24 ? 6 : 4;
+
+    sub_pict->data[0][0] =
+            sub_pict->data[0][1] =
+            sub_pict->data[0][    sub_pict->linesize[0]] =
+            sub_pict->data[0][1+  sub_pict->linesize[0]] = info->v1_codebook[v1_vector*entry_size];
+
+    sub_pict->data[0][2] =
+            sub_pict->data[0][3] =
+            sub_pict->data[0][2+  sub_pict->linesize[0]] =
+            sub_pict->data[0][3+  sub_pict->linesize[0]] = info->v1_codebook[v1_vector*entry_size+1];
+
+    sub_pict->data[0][2*sub_pict->linesize[0]] =
+            sub_pict->data[0][1+2*sub_pict->linesize[0]] =
+            sub_pict->data[0][  3*sub_pict->linesize[0]] =
+            sub_pict->data[0][1+3*sub_pict->linesize[0]] = info->v1_codebook[v1_vector*entry_size+2];
+
+    sub_pict->data[0][2+2*sub_pict->linesize[0]] =
+            sub_pict->data[0][3+2*sub_pict->linesize[0]] =
+            sub_pict->data[0][2+3*sub_pict->linesize[0]] =
+            sub_pict->data[0][3+3*sub_pict->linesize[0]] = info->v1_codebook[v1_vector*entry_size+3];
+
+    if(s->pix_fmt == AV_PIX_FMT_RGB24) {
+        sub_pict->data[1][0] =
+            sub_pict->data[1][1] =
+            sub_pict->data[1][    sub_pict->linesize[1]] =
+            sub_pict->data[1][1+  sub_pict->linesize[1]] = info->v1_codebook[v1_vector*entry_size+4];
+
+        sub_pict->data[2][0] =
+            sub_pict->data[2][1] =
+            sub_pict->data[2][    sub_pict->linesize[2]] =
+            sub_pict->data[2][1+  sub_pict->linesize[2]] = info->v1_codebook[v1_vector*entry_size+5];
+    }
+}
+
+//decodes the V4 vectors in mb into the 4x4 MB pointed to by sub_pict
+static void decode_v4_vector(CinepakEncContext *s, AVPicture *sub_pict, int *v4_vector, strip_info *info)
+{
+    int i, x, y, entry_size = s->pix_fmt == AV_PIX_FMT_RGB24 ? 6 : 4;
+
+    for(i = y = 0; y < 4; y += 2) {
+        for(x = 0; x < 4; x += 2, i++) {
+            sub_pict->data[0][x   +     y*sub_pict->linesize[0]] = info->v4_codebook[v4_vector[i]*entry_size];
+            sub_pict->data[0][x+1 +     y*sub_pict->linesize[0]] = info->v4_codebook[v4_vector[i]*entry_size+1];
+            sub_pict->data[0][x   + (y+1)*sub_pict->linesize[0]] = info->v4_codebook[v4_vector[i]*entry_size+2];
+            sub_pict->data[0][x+1 + (y+1)*sub_pict->linesize[0]] = info->v4_codebook[v4_vector[i]*entry_size+3];
+
+            if(s->pix_fmt == AV_PIX_FMT_RGB24) {
+                sub_pict->data[1][(x>>1) + (y>>1)*sub_pict->linesize[1]] = info->v4_codebook[v4_vector[i]*entry_size+4];
+                sub_pict->data[2][(x>>1) + (y>>1)*sub_pict->linesize[2]] = info->v4_codebook[v4_vector[i]*entry_size+5];
+            }
+        }
+    }
+}
+
+static void copy_mb(CinepakEncContext *s, AVPicture *a, AVPicture *b)
+{
+    int y, p;
+
+    for(y = 0; y < MB_SIZE; y++) {
+        memcpy(a->data[0]+y*a->linesize[0], b->data[0]+y*b->linesize[0],
+               MB_SIZE);
+    }
+
+    if(s->pix_fmt == AV_PIX_FMT_RGB24) {
+        for(p = 1; p <= 2; p++) {
+            for(y = 0; y < MB_SIZE/2; y++) {
+                memcpy(a->data[p] + y*a->linesize[p],
+                       b->data[p] + y*b->linesize[p],
+                       MB_SIZE/2);
+            }
+        }
+    }
+}
+
+static int encode_mode(CinepakEncContext *s, int h, AVPicture *scratch_pict, AVPicture *last_pict, strip_info *info, unsigned char *buf)
+{
+    int x, y, z, flags, bits, temp_size, header_ofs, ret = 0, mb_count = s->w * h / MB_AREA;
+    int needs_extra_bit, should_write_temp;
+    unsigned char temp[64]; //32/2 = 16 V4 blocks at 4 B each -> 64 B
+    mb_info *mb;
+    AVPicture sub_scratch, sub_last;
+
+    //encode codebooks
+    if(info->v1_size)
+        ret += encode_codebook(s, info->v1_codebook, info->v1_size, 0x22, 0x26, buf + ret);
+
+    if(info->v4_size)
+        ret += encode_codebook(s, info->v4_codebook, info->v4_size, 0x20, 0x24, buf + ret);
+
+    //update scratch picture
+    for(z = y = 0; y < h; y += MB_SIZE) {
+        for(x = 0; x < s->w; x += MB_SIZE, z++) {
+            mb = &s->mb[z];
+
+            get_sub_picture(s, x, y, scratch_pict, &sub_scratch);
+
+            if(info->mode == MODE_MC && mb->best_encoding == ENC_SKIP) {
+                get_sub_picture(s, x, y, last_pict, &sub_last);
+                copy_mb(s, &sub_scratch, &sub_last);
+            } else if(info->mode == MODE_V1_ONLY || mb->best_encoding == ENC_V1)
+                decode_v1_vector(s, &sub_scratch, mb->v1_vector, info);
+            else
+                decode_v4_vector(s, &sub_scratch, mb->v4_vector, info);
+        }
+    }
+
+    switch(info->mode) {
+    case MODE_V1_ONLY:
+        //av_log(s->avctx, AV_LOG_INFO, "mb_count = %i\n", mb_count);
+        ret += write_chunk_header(buf + ret, 0x32, mb_count);
+
+        for(x = 0; x < mb_count; x++)
+            buf[ret++] = s->mb[x].v1_vector;
+
+        break;
+    case MODE_V1_V4:
+        //remember header position
+        header_ofs = ret;
+        ret += CHUNK_HEADER_SIZE;
+
+        for(x = 0; x < mb_count; x += 32) {
+            flags = 0;
+            for(y = x; y < FFMIN(x+32, mb_count); y++)
+                if(s->mb[y].best_encoding == ENC_V4)
+                    flags |= 1 << (31 - y + x);
+
+            AV_WB32(&buf[ret], flags);
+            ret += 4;
+
+            for(y = x; y < FFMIN(x+32, mb_count); y++) {
+                mb = &s->mb[y];
+
+                if(mb->best_encoding == ENC_V1)
+                    buf[ret++] = mb->v1_vector;
+                else
+                    for(z = 0; z < 4; z++)
+                        buf[ret++] = mb->v4_vector[z];
+            }
+        }
+
+        write_chunk_header(buf + header_ofs, 0x30, ret - header_ofs - CHUNK_HEADER_SIZE);
+
+        break;
+    case MODE_MC:
+        //remember header position
+        header_ofs = ret;
+        ret += CHUNK_HEADER_SIZE;
+        flags = bits = temp_size = 0;
+        
+        for(x = 0; x < mb_count; x++) {
+            mb = &s->mb[x];
+            flags |= (mb->best_encoding != ENC_SKIP) << (31 - bits++);
+            needs_extra_bit = 0;
+            should_write_temp = 0;
+
+            if(mb->best_encoding != ENC_SKIP) {
+                if(bits < 32)
+                    flags |= (mb->best_encoding == ENC_V4) << (31 - bits++);
+                else
+                    needs_extra_bit = 1;
+            }
+
+            if(bits == 32) {
+                AV_WB32(&buf[ret], flags);
+                ret += 4;
+                flags = bits = 0;
+
+                if(mb->best_encoding == ENC_SKIP || needs_extra_bit) {
+                    memcpy(&buf[ret], temp, temp_size);
+                    ret += temp_size;
+                    temp_size = 0;
+                } else
+                    should_write_temp = 1;
+            }
+
+            if(needs_extra_bit) {
+                flags = (mb->best_encoding == ENC_V4) << 31;
+                bits = 1;
+            }
+
+            if(mb->best_encoding == ENC_V1)
+                temp[temp_size++] = mb->v1_vector;
+            else if(mb->best_encoding == ENC_V4)
+                for(z = 0; z < 4; z++)
+                    temp[temp_size++] = mb->v4_vector[z];
+
+            if(should_write_temp) {
+                memcpy(&buf[ret], temp, temp_size);
+                ret += temp_size;
+                temp_size = 0;
+            }
+        }
+
+        if(bits > 0) {
+            AV_WB32(&buf[ret], flags);
+            ret += 4;
+            memcpy(&buf[ret], temp, temp_size);
+            ret += temp_size;
+        }
+
+        write_chunk_header(buf + header_ofs, 0x31, ret - header_ofs - CHUNK_HEADER_SIZE);
+        
+        break;
+    }
+
+    return ret;
+}
+
+//computes distortion of 4x4 MB in b compared to a
+static int compute_mb_distortion(CinepakEncContext *s, AVPicture *a, AVPicture *b)
+{
+    int x, y, p, d, ret = 0;
+
+    for(y = 0; y < MB_SIZE; y++) {
+        for(x = 0; x < MB_SIZE; x++) {
+            d = a->data[0][x + y*a->linesize[0]] - b->data[0][x + y*b->linesize[0]];
+            ret += d*d;
+        }
+    }
+
+    if(s->pix_fmt == AV_PIX_FMT_RGB24) {
+        for(p = 1; p <= 2; p++) {
+            for(y = 0; y < MB_SIZE/2; y++) {
+                for(x = 0; x < MB_SIZE/2; x++) {
+                    d = a->data[p][x + y*a->linesize[p]] - b->data[p][x + y*b->linesize[p]];
+                    ret += d*d;
+                }
+            }
+        }
+    }
+
+    return ret;
+}
+
+// return the possibly adjusted size of the codebook
+#define CERTAIN(x) ((x)!=ENC_UNCERTAIN)
+static int quantize(CinepakEncContext *s, int h, AVPicture *pict,
+                    int v1mode, strip_info *info,
+                    mb_encoding encoding)
+{
+    int x, y, i, j, k, x2, y2, x3, y3, plane, shift, mbn;
+    int entry_size = s->pix_fmt == AV_PIX_FMT_RGB24 ? 6 : 4;
+    int *codebook = v1mode ? info->v1_codebook : info->v4_codebook;
+    int size = v1mode ? info->v1_size : info->v4_size;
+    int64_t total_error = 0;
+    uint8_t vq_pict_buf[(MB_AREA*3)/2];
+    AVPicture sub_pict, vq_pict;
+
+    for(mbn = i = y = 0; y < h; y += MB_SIZE) {
+        for(x = 0; x < s->w; x += MB_SIZE, ++mbn) {
+            int *base;
+
+            if(CERTAIN(encoding)) {
+// use for the training only the blocks known to be to be encoded [sic:-]
+               if(s->mb[mbn].best_encoding != encoding) continue;
+            }
+
+            base = s->codebook_input + i*entry_size;
+            if(v1mode) {
+                //subsample
+                for(j = y2 = 0; y2 < entry_size; y2 += 2) {
+                    for(x2 = 0; x2 < 4; x2 += 2, j++) {
+                        plane = y2 < 4 ? 0 : 1 + (x2 >> 1);
+                        shift = y2 < 4 ? 0 : 1;
+                        x3 = shift ? 0 : x2;
+                        y3 = shift ? 0 : y2;
+                        base[j] = (pict->data[plane][((x+x3) >> shift) +      ((y+y3) >> shift)      * pict->linesize[plane]] +
+                                   pict->data[plane][((x+x3) >> shift) + 1 +  ((y+y3) >> shift)      * pict->linesize[plane]] +
+                                   pict->data[plane][((x+x3) >> shift) +     (((y+y3) >> shift) + 1) * pict->linesize[plane]] +
+                                   pict->data[plane][((x+x3) >> shift) + 1 + (((y+y3) >> shift) + 1) * pict->linesize[plane]]) >> 2;
+                    }
+                }
+            } else {
+                //copy
+                for(j = y2 = 0; y2 < MB_SIZE; y2 += 2) {
+                    for(x2 = 0; x2 < MB_SIZE; x2 += 2) {
+                        for(k = 0; k < entry_size; k++, j++) {
+                            plane = k >= 4 ? k - 3 : 0;
+                            
+                            if(k >= 4) {
+                                x3 = (x+x2) >> 1;
+                                y3 = (y+y2) >> 1;
+                            } else {
+                                x3 = x + x2 + (k & 1);
+                                y3 = y + y2 + (k >> 1);
+                            }
+
+                            base[j] = pict->data[plane][x3 + y3*pict->linesize[plane]];
+                        }
+                    }
+                }
+            }
+            i += v1mode ? 1 : 4;
+        }
+    }
+//    if(i < mbn*(v1mode ? 1 : 4)) {
+//        av_log(s->avctx, AV_LOG_INFO, "reducing training set for %s from %i to %i (encoding %i)\n", v1mode?"v1":"v4", mbn*(v1mode ? 1 : 4), i, encoding);
+//    }
+
+    if(i < size) {
+        //av_log(s->avctx, (CERTAIN(encoding) ? AV_LOG_ERROR : AV_LOG_INFO), "WOULD WASTE: %s cbsize %i bigger than training set size %i (encoding %i)\n", v1mode?"v1":"v4", size, i, encoding);
+        size = i;
+        if(i == 0) // empty training set, nothing to do
+          return 0;
+    }
+
+    ff_init_elbg(s->codebook_input, entry_size, i, codebook, size, 1, s->codebook_closest, &s->randctx);
+    ff_do_elbg(s->codebook_input, entry_size, i, codebook, size, 1, s->codebook_closest, &s->randctx);
+
+    //setup vq_pict, which contains a single MB
+    vq_pict.data[0] = vq_pict_buf;
+    vq_pict.linesize[0] = MB_SIZE;
+    vq_pict.data[1] = &vq_pict_buf[MB_AREA];
+    vq_pict.data[2] = vq_pict.data[1] + (MB_AREA >> 2);
+    vq_pict.linesize[1] = vq_pict.linesize[2] = MB_SIZE >> 1;
+
+    //copy indices
+    for(i = j = y = 0; y < h; y += MB_SIZE) {
+        for(x = 0; x < s->w; x += MB_SIZE, j++) {
+            mb_info *mb = &s->mb[j];
+// skip uninteresting blocks if we know their preferred encoding
+            if(CERTAIN(encoding) && mb->best_encoding != encoding)
+                continue;
+
+            //point sub_pict to current MB
+            get_sub_picture(s, x, y, pict, &sub_pict);
+
+            if(v1mode) {
+                mb->v1_vector = s->codebook_closest[i];
+
+                //fill in vq_pict with V1 data
+                decode_v1_vector(s, &vq_pict, mb->v1_vector, info);
+
+                mb->v1_error = compute_mb_distortion(s, &sub_pict, &vq_pict);
+                total_error += mb->v1_error;
+            } else {
+                for(k = 0; k < 4; k++)
+                    mb->v4_vector[k] = s->codebook_closest[i+k];
+
+                //fill in vq_pict with V4 data
+                decode_v4_vector(s, &vq_pict, mb->v4_vector, info);
+
+                mb->v4_error = compute_mb_distortion(s, &sub_pict, &vq_pict);
+                total_error += mb->v4_error;
+            }
+            i += v1mode ? 1 : 4;
+        }
+    }
+// check that we did it right in the beginning of the function
+    assert(i >= size); // training set is no smaller than the codebook
+
+    //av_log(s->avctx, AV_LOG_INFO, "isv1 %i size= %i i= %i error %lli\n", v1mode, size, i, (long long int)total_error);
+
+    return size;
+}
+
+static void calculate_skip_errors(CinepakEncContext *s, int h, AVPicture *last_pict, AVPicture *pict, strip_info *info)
+{
+    int x, y, i;
+    AVPicture sub_last, sub_pict;
+
+    for(i = y = 0; y < h; y += MB_SIZE) {
+        for(x = 0; x < s->w; x += MB_SIZE, i++) {
+            get_sub_picture(s, x, y, last_pict, &sub_last);
+            get_sub_picture(s, x, y, pict,      &sub_pict);
+
+            s->mb[i].skip_error = compute_mb_distortion(s, &sub_last, &sub_pict);
+        }
+    }
+}
+
+static void write_strip_header(CinepakEncContext *s, int y, int h, int keyframe, unsigned char *buf, int strip_size)
+{
+// actually we are exclusively using intra strip coding (how much can we win
+// otherwise? how to choose which part of a codebook to update?),
+// keyframes are different only because we disallow ENC_SKIP on them -- rl
+// (besides, the logic here used to be inverted: )
+//    buf[0] = keyframe ? 0x11: 0x10;
+    buf[0] = keyframe ? 0x10: 0x11;
+    AV_WB24(&buf[1], strip_size + STRIP_HEADER_SIZE);
+//    AV_WB16(&buf[4], y); /* using absolute y values works -- rl */
+    AV_WB16(&buf[4], 0); /* using relative values works as well -- rl */
+    AV_WB16(&buf[6], 0);
+//    AV_WB16(&buf[8], y+h); /* using absolute y values works -- rl */
+    AV_WB16(&buf[8], h); /* using relative values works as well -- rl */
+    AV_WB16(&buf[10], s->w);
+    //av_log(s->avctx, AV_LOG_INFO, "write_strip_header() %x keyframe=%d\n", buf[0], keyframe);
+}
+
+static int rd_strip(CinepakEncContext *s, int y, int h, int keyframe, AVPicture *last_pict, AVPicture *pict, AVPicture *scratch_pict, unsigned char *buf, int64_t *best_score
+#ifdef CINEPAK_REPORT_SERR
+, int64_t *best_serr
+#endif
+)
+{
+    int64_t score = 0;
+#ifdef CINEPAK_REPORT_SERR
+    int64_t serr;
+#endif
+    int best_size = 0;
+    strip_info info;
+// for codebook optimization:
+    int new_v1_size, new_v4_size;
+
+    if(!keyframe)
+        calculate_skip_errors(s, h, last_pict, pict, &info);
+
+    //try some powers of 4 for the size of the codebooks
+    //constraint the v4 codebook to be no bigger than v1 one,
+    //(and no less than v1_size/4)
+    //thus making v1 preferable and possibly losing small details? should be ok
+#define SMALLEST_CODEBOOK 1
+    for(int v1enough = 0, v1_size = SMALLEST_CODEBOOK; v1_size <= CODEBOOK_MAX && !v1enough; v1_size <<= 2) {
+        for(int v4enough = 0, v4_size = 0; v4_size <= v1_size && !v4enough; v4_size = v4_size ? v4_size << 2 : v1_size >= SMALLEST_CODEBOOK << 2 ? v1_size >> 2 : SMALLEST_CODEBOOK) {
+            //try all modes
+            for(CinepakMode mode = 0; mode < MODE_COUNT; mode++) {
+                //don't allow MODE_MC in intra frames
+                if(keyframe && mode == MODE_MC)
+                    continue;
+
+                if(mode == MODE_V1_ONLY) {
+                    info.v1_size = v1_size;
+// the size may shrink even before optimizations if the input is short:
+                    info.v1_size = quantize(s, h, pict, 1, &info, ENC_UNCERTAIN);
+                    if(info.v1_size < v1_size)
+// too few eligible blocks, no sense in trying bigger sizes
+                        v1enough = 1;
+                }
+
+                if(mode != MODE_V1_ONLY) {
+                    // if v4 codebook is empty then only allow V1-only mode
+                    if(!v4_size)
+                        continue;
+
+                    if(mode == MODE_V1_V4) {
+                        info.v4_size = v4_size;
+                        info.v4_size = quantize(s, h, pict, 0, &info, ENC_UNCERTAIN);
+                        if(info.v4_size < v4_size)
+// too few eligible blocks, no sense in trying bigger sizes
+                            v4enough = 1;
+                    }
+                } else {
+                    info.v4_size = 0;
+                }
+
+                info.mode = mode;
+// choose the best encoding per block, based on current experience
+                score = calculate_mode_score(s, h, &info, 0
+#ifdef CINEPAK_REPORT_SERR
+, &serr
+#endif
+);
+
+                if(mode != MODE_V1_ONLY){
+// recompute the codebooks, omitting the extra blocks
+// we may come here with more blocks to encode than before
+                    info.v4_size = v4_size;
+                    new_v4_size = quantize(s, h, pict, 0, &info, ENC_V4);
+
+                    if(new_v4_size < info.v4_size) {
+                        //av_log(s->avctx, AV_LOG_INFO, "mode %i, %3i, %3i: cut v4 codebook to %i entries\n", mode, v1_size, v4_size, new_v4_size);
+                        info.v4_size = new_v4_size;
+                    }
+// we may come here with more blocks to encode than before
+                    info.v1_size = v1_size;
+                    new_v1_size = quantize(s, h, pict, 1, &info, ENC_V1);
+
+                    if(new_v1_size < info.v1_size){
+                        //av_log(s->avctx, AV_LOG_INFO, "mode %i, %3i, %3i: cut v1 codebook to %i entries\n", mode, v1_size, v4_size, new_v1_size);
+                        info.v1_size = new_v1_size;
+                    }
+// calculate the resulting score
+// (do not move blocks to different encodings now,
+// as some blocks may have got bigger errors
+// despite a smaller training set)
+                    score = calculate_mode_score(s, h, &info, 1
+#ifdef CINEPAK_REPORT_SERR
+, &serr
+#endif
+);
+                }
+
+                //av_log(s->avctx, AV_LOG_INFO, "%3i %3i score = %lli\n", v1_size, v4_size, (long long int)score);
+
+                if(best_size == 0 || score < *best_score) {
+
+                    *best_score = score;
+#ifdef CINEPAK_REPORT_SERR
+                    *best_serr = serr;
+#endif
+                    best_size = encode_mode(s, h, scratch_pict, last_pict, &info, s->strip_buf + STRIP_HEADER_SIZE);
+
+                    //av_log(s->avctx, AV_LOG_INFO, "mode %i, %3i, %3i: %18lli %i B", mode, info.v1_size, info.v4_size, (long long int)score, best_size);
+                    //av_log(s->avctx, AV_LOG_INFO, "\n");
+#ifdef CINEPAK_REPORT_SERR
+                    av_log(s->avctx, AV_LOG_INFO, "mode %i, %3i, %3i: %18lli %i B\n", mode, v1_size, v4_size, (long long int)serr, best_size);
+#endif
+
+#ifdef CINEPAKENC_DEBUG
+                    //save MB encoding choices
+                    memcpy(s->best_mb, s->mb, mb_count*sizeof(mb_info));
+#endif
+                    
+                    //memcpy(strip_temp + STRIP_HEADER_SIZE, strip_temp, best_size);
+                    write_strip_header(s, y, h, keyframe, s->strip_buf, best_size);
+
+                }
+            }
+        }
+    }
+
+#ifdef CINEPAKENC_DEBUG
+    //gather stats. this will only work properly of MAX_STRIPS == 1
+    if(best_info.mode == MODE_V1_ONLY) {
+        s->num_v1_mode++;
+        s->num_v1_encs += s->w*h/MB_AREA;
+    } else {
+        if(best_info.mode == MODE_V1_V4)
+            s->num_v4_mode++;
+        else
+            s->num_mc_mode++;
+
+        int x;
+        for(x = 0; x < s->w*h/MB_AREA; x++)
+            if(s->best_mb[x].best_encoding == ENC_V1)
+                s->num_v1_encs++;
+            else if(s->best_mb[x].best_encoding == ENC_V4)
+                s->num_v4_encs++;
+            else
+                s->num_skips++;
+    }
+#endif
+
+    best_size += STRIP_HEADER_SIZE;
+    memcpy(buf, s->strip_buf, best_size);
+
+    return best_size;
+}
+
+static int write_cvid_header(CinepakEncContext *s, unsigned char *buf, int num_strips, int data_size)
+{
+    buf[0] = 0;
+    AV_WB24(&buf[1], data_size + CVID_HEADER_SIZE);
+    AV_WB16(&buf[4], s->w);
+    AV_WB16(&buf[6], s->h);
+    AV_WB16(&buf[8], num_strips);
+
+    return CVID_HEADER_SIZE;
+}
+
+static int rd_frame(CinepakEncContext *s, AVFrame *frame, int isakeyframe, unsigned char *buf, int buf_size)
+{
+    int num_strips, strip, i, y, nexty, size, temp_size, best_size;
+    AVPicture last_pict, pict, scratch_pict;
+    int64_t best_score = 0, score, score_temp;
+#ifdef CINEPAK_REPORT_SERR
+    int64_t best_serr = 0, serr, serr_temp;
+#endif
+
+    int best_nstrips;
+
+    if(s->pix_fmt == AV_PIX_FMT_RGB24) {
+        int x;
+// build a copy of the given frame in the correct colorspace
+        for(y = 0; y < s->h; y += 2) {
+            for(x = 0; x < s->w; x += 2) {
+                uint8_t *ir[2]; int r, g, b, rr, gg, bb;
+                ir[0] = ((AVPicture*)frame)->data[0] + x*3 + y*((AVPicture*)frame)->linesize[0];
+                ir[1] = ir[0] + ((AVPicture*)frame)->linesize[0];
+                get_sub_picture(s, x, y, (AVPicture*)&s->input_frame, &scratch_pict);
+                r = g = b = 0;
+                for(i=0; i<4; ++i) {
+                    int i1, i2;
+                    i1 = (i&1); i2 = (i>=2);
+                    rr = ir[i2][i1*3+0];
+                    gg = ir[i2][i1*3+1];
+                    bb = ir[i2][i1*3+2];
+                    r += rr; g += gg; b += bb;
+// "Y"
+                    rr = 0.2857*rr + 0.5714*gg + 0.1429*bb;
+                    if(      rr <   0) rr =   0;
+                    else if (rr > 255) rr = 255;
+                    scratch_pict.data[0][i1 + i2*scratch_pict.linesize[0]] = rr;
+                }
+                r /= 4; g /= 4; b /= 4;
+// "U"
+                rr = -0.1429*r - 0.2857*g + 0.4286*b;
+                if(      rr < -128) rr = -128;
+                else if (rr >  127) rr =  127;
+                scratch_pict.data[1][0] = rr + 128; // quantize needs unsigned
+// "V"
+                rr = 0.3571*r - 0.2857*g - 0.0714*b;
+                if(      rr < -128) rr = -128;
+                else if (rr >  127) rr =  127;
+                scratch_pict.data[2][0] = rr + 128; // quantize needs unsigned
+            }
+        }
+    }
+
+    //TODO: support encoding zero strips (meaning skip the whole frame)
+    for(num_strips = s->min_strips; num_strips <= s->max_strips && num_strips <= s->h / MB_SIZE; num_strips++) {
+        score = 0;
+        size = 0;
+#ifdef CINEPAK_REPORT_SERR
+        serr = 0;
+#endif
+
+        for(y = 0, strip = 1; y < s->h; strip++, y = nexty) {
+            int strip_height;
+
+            nexty = strip * s->h / num_strips; // <= s->h
+            //make nexty the next multiple of 4 if not already there
+            if(nexty & 3)
+                nexty += 4 - (nexty & 3);
+
+            strip_height = nexty - y;
+            if(strip_height <= 0) { // can this ever happen?
+                av_log(s->avctx, AV_LOG_INFO, "skipping zero height strip %i of %i\n", strip, num_strips);
+                continue;
+            }
+
+            if(s->pix_fmt == AV_PIX_FMT_RGB24)
+                get_sub_picture(s, 0, y, (AVPicture*)&s->input_frame,    &pict);
+            else
+                get_sub_picture(s, 0, y, (AVPicture*)frame,              &pict);
+            get_sub_picture(s, 0, y, (AVPicture*)&s->last_frame,    &last_pict);
+            get_sub_picture(s, 0, y, (AVPicture*)&s->scratch_frame, &scratch_pict);
+
+            if((temp_size = rd_strip(s, y, strip_height, isakeyframe, &last_pict, &pict, &scratch_pict, s->frame_buf + size + CVID_HEADER_SIZE, &score_temp
+#ifdef CINEPAK_REPORT_SERR
+, &serr_temp
+#endif
+)) < 0)
+                return temp_size;
+
+            score += score_temp;
+#ifdef CINEPAK_REPORT_SERR
+            serr += serr_temp;
+#endif
+            size += temp_size;
+            //av_log(s->avctx, AV_LOG_INFO, "strip %d, isakeyframe=%d", strip, isakeyframe);
+            //av_log(s->avctx, AV_LOG_INFO, "\n");
+        }
+
+        if(best_score == 0 || score < best_score) {
+            best_score = score;
+#ifdef CINEPAK_REPORT_SERR
+            best_serr = serr;
+#endif
+            best_size = size + write_cvid_header(s, s->frame_buf, num_strips, size);
+            //av_log(s->avctx, AV_LOG_INFO, "best number of strips so far: %2i, %12lli, %i B\n", num_strips, (long long int)score, best_size);
+#ifdef CINEPAK_REPORT_SERR
+            av_log(s->avctx, AV_LOG_INFO, "best number of strips so far: %2i, %12lli, %i B\n", num_strips, (long long int)serr, best_size);
+#endif
+
+            FFSWAP(AVFrame, s->best_frame, s->scratch_frame);
+            memcpy(buf, s->frame_buf, best_size);
+            best_nstrips = num_strips;
+        }
+// avoid trying too many strip numbers without a real reason
+// (this makes the processing of the very first frame faster)
+        if(num_strips - best_nstrips > 4)
+            break;
+    }
+
+// let the number of strips slowly adapt to the changes in the contents,
+// compared to full bruteforcing every time this will occasionally lead
+// to some r/d performance loss but makes encoding up to several times faster
+#ifdef CINEPAK_AGGRESSIVE_STRIP_NUMBER_ADAPTIVITY
+    s->max_strips = best_nstrips + 4;
+    if(s->max_strips >= MAX_STRIPS)
+        s->max_strips = MAX_STRIPS;
+    s->min_strips = best_nstrips - 4;
+    if(s->min_strips < MIN_STRIPS)
+        s->min_strips = MIN_STRIPS;
+#else
+    if(best_nstrips == s->max_strips) { // let us try to step up
+        s->max_strips = best_nstrips + 1;
+        if(s->max_strips >= MAX_STRIPS)
+            s->max_strips = MAX_STRIPS;
+    } else { // try to step down
+        s->max_strips = best_nstrips;
+    }
+    s->min_strips = s->max_strips - 1;
+    if(s->min_strips < MIN_STRIPS)
+        s->min_strips = MIN_STRIPS;
+#endif
+
+    return best_size;
+}
+
+static int cinepak_encode_frame(AVCodecContext *avctx, AVPacket *pkt,
+                                const AVFrame *frame, int *got_packet)
+{
+    CinepakEncContext *s = avctx->priv_data;
+    int ret;
+    
+    s->lambda = frame->quality ? frame->quality - 1 : 2 * FF_LAMBDA_SCALE;
+
+    if ((ret = ff_alloc_packet2(avctx, pkt, s->frame_buf_size)) < 0)
+        return ret;
+    ret = rd_frame(s, frame, (s->curframe == 0), pkt->data, s->frame_buf_size);
+    pkt->size = ret;
+    if (s->curframe == 0)
+        pkt->flags |= AV_PKT_FLAG_KEY;
+    *got_packet = 1;
+
+    avctx->coded_frame = frame;
+
+    FFSWAP(AVFrame, s->last_frame, s->best_frame);
+
+    if (++s->curframe >= s->keyint)
+        s->curframe = 0;
+
+    return 0;
+}
+
+static av_cold int cinepak_encode_end(AVCodecContext *avctx)
+{
+    CinepakEncContext *s = avctx->priv_data;
+    int x;
+
+    av_free(s->codebook_input);
+    av_free(s->codebook_closest);
+    av_free(s->strip_buf);
+    av_free(s->frame_buf);
+    av_free(s->mb);
+#ifdef CINEPAKENC_DEBUG
+    av_free(s->best_mb);
+#endif
+
+    for(x = 0; x < 3; x++)
+        av_free(s->pict_bufs[x]);
+
+#ifdef CINEPAKENC_DEBUG
+    av_log(avctx, AV_LOG_INFO, "strip coding stats: %i V1 mode, %i V4 mode, %i MC mode (%i V1 encs, %i V4 encs, %i skips)\n",
+        s->num_v1_mode, s->num_v4_mode, s->num_mc_mode, s->num_v1_encs, s->num_v4_encs, s->num_skips);
+#endif
+
+    return 0;
+}
+
+AVCodec ff_cinepak_encoder = {
+    .name           = "cinepak",
+    .type           = AVMEDIA_TYPE_VIDEO,
+    .id             = AV_CODEC_ID_CINEPAK,
+    .priv_data_size = sizeof(CinepakEncContext),
+    .init           = cinepak_encode_init,
+    .encode2        = cinepak_encode_frame,
+    .close          = cinepak_encode_end,
+    .pix_fmts       = (const enum AVPixelFormat[]){AV_PIX_FMT_RGB24, AV_PIX_FMT_GRAY8, AV_PIX_FMT_NONE},
+    .long_name      = NULL_IF_CONFIG_SMALL("Cinepak / CVID"),
+};
-- 
1.6.1


>From bc49313e87c1711d731a79ca6a4a6e089bb3b1c5 Mon Sep 17 00:00:00 2001
From: Rl <addr-see-the-website at aetey.se>
Date: Sun, 12 Jan 2014 18:21:41 +0100
Subject: [PATCH 2/2] Fix, now using the proper elbg prefix.

---
 libavcodec/cinepakenc.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/libavcodec/cinepakenc.c b/libavcodec/cinepakenc.c
index 8356d36..d815c80 100644
--- a/libavcodec/cinepakenc.c
+++ b/libavcodec/cinepakenc.c
@@ -764,8 +764,8 @@ static int quantize(CinepakEncContext *s, int h, AVPicture *pict,
           return 0;
     }
 
-    ff_init_elbg(s->codebook_input, entry_size, i, codebook, size, 1, s->codebook_closest, &s->randctx);
-    ff_do_elbg(s->codebook_input, entry_size, i, codebook, size, 1, s->codebook_closest, &s->randctx);
+    avpriv_init_elbg(s->codebook_input, entry_size, i, codebook, size, 1, s->codebook_closest, &s->randctx);
+    avpriv_do_elbg(s->codebook_input, entry_size, i, codebook, size, 1, s->codebook_closest, &s->randctx);
 
     //setup vq_pict, which contains a single MB
     vq_pict.data[0] = vq_pict_buf;
-- 
1.6.1



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