avcodec/roqvideo: Use dedicated context for encoder

Up until now, the RoQ video decoder and encoder used the same context;
and said context contained several fields that are only used by the
encoder. This commit changes this and uses a dedicated context for the
encoder; it contains the common context as first element in order to use
functions common to the de- and encoder.

Reviewed-by: Paul B Mahol <onemda@gmail.com>
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>

2 files changed, 127 insertions, 119 deletions

diff --git a/libavcodec/roqvideo.h b/libavcodec/roqvideo.h
index f47b2c8e6f..8318b6e5a0 100644
--- a/libavcodec/roqvideo.h
+++ b/libavcodec/roqvideo.h
@@ -22,9 +22,7 @@
 #ifndef AVCODEC_ROQVIDEO_H
 #define AVCODEC_ROQVIDEO_H
 
-#include "libavutil/lfg.h"
 #include "avcodec.h"
-#include "bytestream.h"
 
 typedef struct roq_cell {
     unsigned char y[4];
@@ -39,39 +37,15 @@ typedef struct motion_vect {
     int d[2];
 } motion_vect;
 
-struct RoqTempData;
-
 typedef struct RoqContext {
-
     const AVClass *class;
     AVCodecContext *avctx;
     AVFrame *last_frame;
     AVFrame *current_frame;
-    int first_frame;
+    int width, height;
 
     roq_cell cb2x2[256];
     roq_qcell cb4x4[256];
-
-    int width, height;
-
-    /* Encoder only data */
-    AVLFG randctx;
-    uint64_t lambda;
-
-    motion_vect *this_motion4;
-    motion_vect *last_motion4;
-
-    motion_vect *this_motion8;
-    motion_vect *last_motion8;
-
-    unsigned int framesSinceKeyframe;
-
-    const AVFrame *frame_to_enc;
-    uint8_t *out_buf;
-    struct RoqTempData *tmpData;
-
-    int quake3_compat; // Quake 3 compatibility option
-
 } RoqContext;
 
 #define RoQ_INFO              0x1001
diff --git a/libavcodec/roqvideoenc.c b/libavcodec/roqvideoenc.c
index dc6a63099d..f52c1f5454 100644
--- a/libavcodec/roqvideoenc.c
+++ b/libavcodec/roqvideoenc.c
@@ -57,6 +57,7 @@
 #include <string.h>
 
 #include "libavutil/attributes.h"
+#include "libavutil/lfg.h"
 #include "libavutil/opt.h"
 #include "roqvideo.h"
 #include "bytestream.h"
@@ -77,6 +78,27 @@
 /* The cast is useful when multiplying it by INT_MAX */
 #define ROQ_LAMBDA_SCALE ((uint64_t) FF_LAMBDA_SCALE)
 
+typedef struct RoqEncContext {
+    RoqContext common;
+    AVLFG randctx;
+    uint64_t lambda;
+
+    motion_vect *this_motion4;
+    motion_vect *last_motion4;
+
+    motion_vect *this_motion8;
+    motion_vect *last_motion8;
+
+    unsigned int framesSinceKeyframe;
+
+    const AVFrame *frame_to_enc;
+    uint8_t *out_buf;
+    struct RoqTempData *tmpData;
+
+    int first_frame;
+    int quake3_compat; // Quake 3 compatibility option
+} RoqEncContext;
+
 /* Macroblock support functions */
 static void unpack_roq_cell(roq_cell *cell, uint8_t u[4*3])
 {
@@ -143,9 +165,10 @@ static int block_sse(uint8_t * const *buf1, uint8_t * const *buf2, int x1, int y
     return sse;
 }
 
-static int eval_motion_dist(RoqContext *enc, int x, int y, motion_vect vect,
+static int eval_motion_dist(RoqEncContext *enc, int x, int y, motion_vect vect,
                              int size)
 {
+    RoqContext *const roq = &enc->common;
     int mx=vect.d[0];
     int my=vect.d[1];
 
@@ -158,12 +181,12 @@ static int eval_motion_dist(RoqContext *enc, int x, int y, motion_vect vect,
     mx += x;
     my += y;
 
-    if ((unsigned) mx > enc->width-size || (unsigned) my > enc->height-size)
+    if ((unsigned) mx > roq->width-size || (unsigned) my > roq->height-size)
         return INT_MAX;
 
-    return block_sse(enc->frame_to_enc->data, enc->last_frame->data, x, y,
+    return block_sse(enc->frame_to_enc->data, roq->last_frame->data, x, y,
                      mx, my,
-                     enc->frame_to_enc->linesize, enc->last_frame->linesize,
+                     enc->frame_to_enc->linesize, roq->last_frame->linesize,
                      size);
 }
 
@@ -307,7 +330,7 @@ static int index_mb(uint8_t cluster[], uint8_t cb[], int numCB,
         } \
     } while(0)
 
-static void motion_search(RoqContext *enc, int blocksize)
+static void motion_search(RoqEncContext *enc, int blocksize)
 {
     static const motion_vect offsets[8] = {
         {{ 0,-1}},
@@ -320,6 +343,7 @@ static void motion_search(RoqContext *enc, int blocksize)
         {{ 1, 1}},
     };
 
+    RoqContext *const roq = &enc->common;
     int diff, lowestdiff, oldbest;
     int off[3];
     motion_vect bestpick = {{0,0}};
@@ -328,8 +352,7 @@ static void motion_search(RoqContext *enc, int blocksize)
     motion_vect *last_motion;
     motion_vect *this_motion;
     motion_vect vect, vect2;
-
-    int max=(enc->width/blocksize)*enc->height/blocksize;
+    const int max = (roq->width / blocksize) * roq->height / blocksize;
 
     if (blocksize == 4) {
         last_motion = enc->last_motion4;
@@ -339,17 +362,17 @@ static void motion_search(RoqContext *enc, int blocksize)
         this_motion = enc->this_motion8;
     }
 
-    for (i=0; i<enc->height; i+=blocksize)
-        for (j=0; j<enc->width; j+=blocksize) {
+    for (i = 0; i< roq->height; i += blocksize)
+        for (j = 0; j < roq->width; j += blocksize) {
             lowestdiff = eval_motion_dist(enc, j, i, (motion_vect) {{0,0}},
                                           blocksize);
             bestpick.d[0] = 0;
             bestpick.d[1] = 0;
 
             if (blocksize == 4)
-                EVAL_MOTION(enc->this_motion8[(i/8)*(enc->width/8) + j/8]);
+                EVAL_MOTION(enc->this_motion8[(i/8) * (roq->width/8) + j/8]);
 
-            offset = (i/blocksize)*enc->width/blocksize + j/blocksize;
+            offset = (i/blocksize) * roq->width / blocksize + j / blocksize;
             if (offset < max && offset >= 0)
                 EVAL_MOTION(last_motion[offset]);
 
@@ -357,12 +380,12 @@ static void motion_search(RoqContext *enc, int blocksize)
             if (offset < max && offset >= 0)
                 EVAL_MOTION(last_motion[offset]);
 
-            offset = (i/blocksize + 1)*enc->width/blocksize + j/blocksize;
+            offset = (i/blocksize + 1) * roq->width / blocksize + j / blocksize;
             if (offset < max && offset >= 0)
                 EVAL_MOTION(last_motion[offset]);
 
-            off[0]= (i/blocksize)*enc->width/blocksize + j/blocksize - 1;
-            off[1]= off[0] - enc->width/blocksize + 1;
+            off[0]= (i/blocksize) * roq->width / blocksize + j/blocksize - 1;
+            off[1]= off[0] - roq->width / blocksize + 1;
             off[2]= off[1] + 1;
 
             if (i) {
@@ -391,7 +414,7 @@ static void motion_search(RoqContext *enc, int blocksize)
                 }
                 vect = bestpick;
             }
-            offset = (i/blocksize)*enc->width/blocksize + j/blocksize;
+            offset = (i/blocksize) * roq->width / blocksize + j/blocksize;
             this_motion[offset] = bestpick;
         }
 }
@@ -400,8 +423,9 @@ static void motion_search(RoqContext *enc, int blocksize)
  * Get distortion for all options available to a subcel
  */
 static void gather_data_for_subcel(SubcelEvaluation *subcel, int x,
-                                   int y, RoqContext *enc, RoqTempdata *tempData)
+                                   int y, RoqEncContext *enc, RoqTempdata *tempData)
 {
+    RoqContext *const roq = &enc->common;
     uint8_t mb4[4*4*3];
     uint8_t mb2[2*2*3];
     int cluster_index;
@@ -410,25 +434,25 @@ static void gather_data_for_subcel(SubcelEvaluation *subcel, int x,
     static const int bitsUsed[4] = {2, 10, 10, 34};
 
     if (enc->framesSinceKeyframe >= 1) {
-        subcel->motion = enc->this_motion4[y*enc->width/16 + x/4];
+        subcel->motion = enc->this_motion4[y * roq->width / 16 + x / 4];
 
         subcel->eval_dist[RoQ_ID_FCC] =
             eval_motion_dist(enc, x, y,
-                             enc->this_motion4[y*enc->width/16 + x/4], 4);
+                             enc->this_motion4[y * roq->width / 16 + x / 4], 4);
     } else
         subcel->eval_dist[RoQ_ID_FCC] = INT_MAX;
 
     if (enc->framesSinceKeyframe >= 2)
         subcel->eval_dist[RoQ_ID_MOT] = block_sse(enc->frame_to_enc->data,
-                                                  enc->current_frame->data, x,
+                                                  roq->current_frame->data, x,
                                                   y, x, y,
                                                   enc->frame_to_enc->linesize,
-                                                  enc->current_frame->linesize,
+                                                  roq->current_frame->linesize,
                                                   4);
     else
         subcel->eval_dist[RoQ_ID_MOT] = INT_MAX;
 
-    cluster_index = y*enc->width/16 + x/4;
+    cluster_index = y * roq->width / 16 + x / 4;
 
     get_frame_mb(enc->frame_to_enc, x, y, mb4, 4);
 
@@ -463,11 +487,12 @@ static void gather_data_for_subcel(SubcelEvaluation *subcel, int x,
 /**
  * Get distortion for all options available to a cel
  */
-static void gather_data_for_cel(CelEvaluation *cel, RoqContext *enc,
+static void gather_data_for_cel(CelEvaluation *cel, RoqEncContext *enc,
                                 RoqTempdata *tempData)
 {
+    RoqContext *const roq = &enc->common;
     uint8_t mb8[8*8*3];
-    int index = cel->sourceY*enc->width/64 + cel->sourceX/8;
+    int index = cel->sourceY * roq->width / 64 + cel->sourceX/8;
     int i, j, best_dist, divide_bit_use;
 
     int bitsUsed[4] = {2, 10, 10, 0};
@@ -483,11 +508,11 @@ static void gather_data_for_cel(CelEvaluation *cel, RoqContext *enc,
 
     if (enc->framesSinceKeyframe >= 2)
         cel->eval_dist[RoQ_ID_MOT] = block_sse(enc->frame_to_enc->data,
-                                               enc->current_frame->data,
+                                               roq->current_frame->data,
                                                cel->sourceX, cel->sourceY,
                                                cel->sourceX, cel->sourceY,
                                                enc->frame_to_enc->linesize,
-                                               enc->current_frame->linesize,8);
+                                               roq->current_frame->linesize,8);
     else
         cel->eval_dist[RoQ_ID_MOT] = INT_MAX;
 
@@ -537,8 +562,9 @@ static void gather_data_for_cel(CelEvaluation *cel, RoqContext *enc,
         }
 }
 
-static void remap_codebooks(RoqContext *enc, RoqTempdata *tempData)
+static void remap_codebooks(RoqEncContext *enc, RoqTempdata *tempData)
 {
+    RoqContext *const roq = &enc->common;
     int i, j, idx=0;
 
     /* Make remaps for the final codebook usage */
@@ -547,7 +573,7 @@ static void remap_codebooks(RoqContext *enc, RoqTempdata *tempData)
             tempData->i2f4[i] = idx;
             tempData->f2i4[idx] = i;
             for (j=0; j<4; j++)
-                tempData->codebooks.usedCB2[enc->cb4x4[i].idx[j]]++;
+                tempData->codebooks.usedCB2[roq->cb4x4[i].idx[j]]++;
             idx++;
         }
     }
@@ -569,8 +595,9 @@ static void remap_codebooks(RoqContext *enc, RoqTempdata *tempData)
 /**
  * Write codebook chunk
  */
-static void write_codebooks(RoqContext *enc, RoqTempdata *tempData)
+static void write_codebooks(RoqEncContext *enc, RoqTempdata *tempData)
 {
+    RoqContext *const roq = &enc->common;
     int i, j;
     uint8_t **outp= &enc->out_buf;
 
@@ -581,14 +608,14 @@ static void write_codebooks(RoqContext *enc, RoqTempdata *tempData)
         bytestream_put_byte(outp, tempData->numCB2);
 
         for (i=0; i<tempData->numCB2; i++) {
-            bytestream_put_buffer(outp, enc->cb2x2[tempData->f2i2[i]].y, 4);
-            bytestream_put_byte(outp, enc->cb2x2[tempData->f2i2[i]].u);
-            bytestream_put_byte(outp, enc->cb2x2[tempData->f2i2[i]].v);
+            bytestream_put_buffer(outp, roq->cb2x2[tempData->f2i2[i]].y, 4);
+            bytestream_put_byte(outp, roq->cb2x2[tempData->f2i2[i]].u);
+            bytestream_put_byte(outp, roq->cb2x2[tempData->f2i2[i]].v);
         }
 
         for (i=0; i<tempData->numCB4; i++)
             for (j=0; j<4; j++)
-                bytestream_put_byte(outp, tempData->i2f2[enc->cb4x4[tempData->f2i4[i]].idx[j]]);
+                bytestream_put_byte(outp, tempData->i2f2[roq->cb4x4[tempData->f2i4[i]].idx[j]]);
 
     }
 }
@@ -623,8 +650,11 @@ static void write_typecode(CodingSpool *s, uint8_t type)
     }
 }
 
-static void reconstruct_and_encode_image(RoqContext *enc, RoqTempdata *tempData, int w, int h, int numBlocks)
+static void reconstruct_and_encode_image(RoqEncContext *enc,
+                                         RoqTempdata *tempData,
+                                         int w, int h, int numBlocks)
 {
+    RoqContext *const roq = &enc->common;
     int i, j, k;
     int x, y;
     int subX, subY;
@@ -665,7 +695,7 @@ static void reconstruct_and_encode_image(RoqContext *enc, RoqTempdata *tempData,
             bytestream_put_byte(&spool.args, motion_arg(eval->motion));
 
             write_typecode(&spool, RoQ_ID_FCC);
-            ff_apply_motion_8x8(enc, x, y,
+            ff_apply_motion_8x8(roq, x, y,
                                 eval->motion.d[0], eval->motion.d[1]);
             break;
 
@@ -673,11 +703,11 @@ static void reconstruct_and_encode_image(RoqContext *enc, RoqTempdata *tempData,
             bytestream_put_byte(&spool.args, tempData->i2f4[eval->cbEntry]);
             write_typecode(&spool, RoQ_ID_SLD);
 
-            qcell = enc->cb4x4 + eval->cbEntry;
-            ff_apply_vector_4x4(enc, x  , y  , enc->cb2x2 + qcell->idx[0]);
-            ff_apply_vector_4x4(enc, x+4, y  , enc->cb2x2 + qcell->idx[1]);
-            ff_apply_vector_4x4(enc, x  , y+4, enc->cb2x2 + qcell->idx[2]);
-            ff_apply_vector_4x4(enc, x+4, y+4, enc->cb2x2 + qcell->idx[3]);
+            qcell = roq->cb4x4 + eval->cbEntry;
+            ff_apply_vector_4x4(roq, x  , y  , roq->cb2x2 + qcell->idx[0]);
+            ff_apply_vector_4x4(roq, x+4, y  , roq->cb2x2 + qcell->idx[1]);
+            ff_apply_vector_4x4(roq, x  , y+4, roq->cb2x2 + qcell->idx[2]);
+            ff_apply_vector_4x4(roq, x+4, y+4, roq->cb2x2 + qcell->idx[3]);
             break;
 
         case RoQ_ID_CCC:
@@ -695,7 +725,7 @@ static void reconstruct_and_encode_image(RoqContext *enc, RoqTempdata *tempData,
                     bytestream_put_byte(&spool.args,
                                         motion_arg(eval->subCels[j].motion));
 
-                    ff_apply_motion_4x4(enc, subX, subY,
+                    ff_apply_motion_4x4(roq, subX, subY,
                                         eval->subCels[j].motion.d[0],
                                         eval->subCels[j].motion.d[1]);
                     break;
@@ -704,16 +734,16 @@ static void reconstruct_and_encode_image(RoqContext *enc, RoqTempdata *tempData,
                     bytestream_put_byte(&spool.args,
                                         tempData->i2f4[eval->subCels[j].cbEntry]);
 
-                    qcell = enc->cb4x4 + eval->subCels[j].cbEntry;
+                    qcell = roq->cb4x4 + eval->subCels[j].cbEntry;
 
-                    ff_apply_vector_2x2(enc, subX  , subY  ,
-                                        enc->cb2x2 + qcell->idx[0]);
-                    ff_apply_vector_2x2(enc, subX+2, subY  ,
-                                        enc->cb2x2 + qcell->idx[1]);
-                    ff_apply_vector_2x2(enc, subX  , subY+2,
-                                        enc->cb2x2 + qcell->idx[2]);
-                    ff_apply_vector_2x2(enc, subX+2, subY+2,
-                                        enc->cb2x2 + qcell->idx[3]);
+                    ff_apply_vector_2x2(roq, subX  , subY  ,
+                                        roq->cb2x2 + qcell->idx[0]);
+                    ff_apply_vector_2x2(roq, subX+2, subY  ,
+                                        roq->cb2x2 + qcell->idx[1]);
+                    ff_apply_vector_2x2(roq, subX  , subY+2,
+                                        roq->cb2x2 + qcell->idx[2]);
+                    ff_apply_vector_2x2(roq, subX+2, subY+2,
+                                        roq->cb2x2 + qcell->idx[3]);
                     break;
 
                 case RoQ_ID_CCC:
@@ -722,8 +752,8 @@ static void reconstruct_and_encode_image(RoqContext *enc, RoqTempdata *tempData,
                         bytestream_put_byte(&spool.args,
                                             tempData->i2f2[cb_idx]);
 
-                        ff_apply_vector_2x2(enc, subX + 2*(k&1), subY + (k&2),
-                                            enc->cb2x2 + cb_idx);
+                        ff_apply_vector_2x2(roq, subX + 2*(k&1), subY + (k&2),
+                                            roq->cb2x2 + cb_idx);
                     }
                     break;
                 }
@@ -777,7 +807,7 @@ static void create_clusters(const AVFrame *frame, int w, int h, uint8_t *yuvClus
         }
 }
 
-static int generate_codebook(RoqContext *enc, RoqTempdata *tempdata,
+static int generate_codebook(RoqEncContext *enc, RoqTempdata *tempdata,
                              int *points, int inputCount, roq_cell *results,
                              int size, int cbsize)
 {
@@ -825,11 +855,12 @@ out:
     return ret;
 }
 
-static int generate_new_codebooks(RoqContext *enc, RoqTempdata *tempData)
+static int generate_new_codebooks(RoqEncContext *enc, RoqTempdata *tempData)
 {
     int i, j, ret = 0;
     RoqCodebooks *codebooks = &tempData->codebooks;
-    int max = enc->width*enc->height/16;
+    RoqContext *const roq = &enc->common;
+    int max = roq->width * roq->height / 16;
     uint8_t mb2[3*4];
     roq_cell *results4 = av_malloc(sizeof(roq_cell)*MAX_CBS_4x4*4);
     uint8_t *yuvClusters=av_malloc_array(max, sizeof(int)*6*4);
@@ -842,7 +873,7 @@ static int generate_new_codebooks(RoqContext *enc, RoqTempdata *tempData)
     }
 
     /* Subsample YUV data */
-    create_clusters(enc->frame_to_enc, enc->width, enc->height, yuvClusters);
+    create_clusters(enc->frame_to_enc, roq->width, roq->height, yuvClusters);
 
     /* Cast to integer and apply chroma bias */
     for (i=0; i<max*24; i++) {
@@ -865,23 +896,23 @@ static int generate_new_codebooks(RoqContext *enc, RoqTempdata *tempData)
 
     /* Create 2x2 codebooks */
     if ((ret = generate_codebook(enc, tempData, points, max * 4,
-                                 enc->cb2x2, 2, MAX_CBS_2x2)) < 0)
+                                 roq->cb2x2, 2, MAX_CBS_2x2)) < 0)
         goto out;
 
     codebooks->numCB2 = MAX_CBS_2x2;
 
     /* Unpack 2x2 codebook clusters */
     for (i=0; i<codebooks->numCB2; i++)
-        unpack_roq_cell(enc->cb2x2 + i, codebooks->unpacked_cb2 + i*2*2*3);
+        unpack_roq_cell(roq->cb2x2 + i, codebooks->unpacked_cb2 + i*2*2*3);
 
     /* Index all 4x4 entries to the 2x2 entries, unpack, and enlarge */
     for (i=0; i<codebooks->numCB4; i++) {
         for (j=0; j<4; j++) {
             unpack_roq_cell(&results4[4*i + j], mb2);
             index_mb(mb2, codebooks->unpacked_cb2, codebooks->numCB2,
-                     &enc->cb4x4[i].idx[j], 2);
+                     &roq->cb4x4[i].idx[j], 2);
         }
-        unpack_roq_qcell(codebooks->unpacked_cb2, enc->cb4x4 + i,
+        unpack_roq_qcell(codebooks->unpacked_cb2, roq->cb4x4 + i,
                          codebooks->unpacked_cb4 + i*4*4*3);
         enlarge_roq_mb4(codebooks->unpacked_cb4 + i*4*4*3,
                         codebooks->unpacked_cb4_enlarged + i*8*8*3);
@@ -893,14 +924,15 @@ out:
     return ret;
 }
 
-static int roq_encode_video(RoqContext *enc)
+static int roq_encode_video(RoqEncContext *enc)
 {
     RoqTempdata *tempData = enc->tmpData;
-    int i, ret;
+    RoqContext *const roq = &enc->common;
+    int ret;
 
     memset(tempData, 0, sizeof(*tempData));
 
-    ret = create_cel_evals(enc, tempData);
+    ret = create_cel_evals(roq, tempData);
     if (ret < 0)
         return ret;
 
@@ -914,16 +946,16 @@ static int roq_encode_video(RoqContext *enc)
     }
 
  retry_encode:
-    for (i=0; i<enc->width*enc->height/64; i++)
+    for (int i = 0; i < roq->width * roq->height / 64; i++)
         gather_data_for_cel(tempData->cel_evals + i, enc, tempData);
 
     /* Quake 3 can't handle chunks bigger than 65535 bytes */
     if (tempData->mainChunkSize/8 > 65535 && enc->quake3_compat) {
         if (enc->lambda > 100000) {
-            av_log(enc->avctx, AV_LOG_ERROR, "Cannot encode video in Quake compatible form\n");
+            av_log(roq->avctx, AV_LOG_ERROR, "Cannot encode video in Quake compatible form\n");
             return AVERROR(EINVAL);
         }
-        av_log(enc->avctx, AV_LOG_ERROR,
+        av_log(roq->avctx, AV_LOG_ERROR,
                "Warning, generated a frame too big for Quake (%d > 65535), "
                "now switching to a bigger qscale value.\n",
                tempData->mainChunkSize/8);
@@ -942,11 +974,11 @@ static int roq_encode_video(RoqContext *enc)
 
     write_codebooks(enc, tempData);
 
-    reconstruct_and_encode_image(enc, tempData, enc->width, enc->height,
-                                 enc->width*enc->height/64);
+    reconstruct_and_encode_image(enc, tempData, roq->width, roq->height,
+                                 roq->width * roq->height / 64);
 
     /* Rotate frame history */
-    FFSWAP(AVFrame *, enc->current_frame, enc->last_frame);
+    FFSWAP(AVFrame *,    roq->current_frame,   roq->last_frame);
     FFSWAP(motion_vect *, enc->last_motion4, enc->this_motion4);
     FFSWAP(motion_vect *, enc->last_motion8, enc->this_motion8);
 
@@ -960,10 +992,10 @@ static int roq_encode_video(RoqContext *enc)
 
 static av_cold int roq_encode_end(AVCodecContext *avctx)
 {
-    RoqContext *enc = avctx->priv_data;
+    RoqEncContext *const enc = avctx->priv_data;
 
-    av_frame_free(&enc->current_frame);
-    av_frame_free(&enc->last_frame);
+    av_frame_free(&enc->common.current_frame);
+    av_frame_free(&enc->common.last_frame);
 
     av_freep(&enc->tmpData);
     av_freep(&enc->this_motion4);
@@ -976,11 +1008,12 @@ static av_cold int roq_encode_end(AVCodecContext *avctx)
 
 static av_cold int roq_encode_init(AVCodecContext *avctx)
 {
-    RoqContext *enc = avctx->priv_data;
+    RoqEncContext *const enc = avctx->priv_data;
+    RoqContext    *const roq = &enc->common;
 
     av_lfg_init(&enc->randctx, 1);
 
-    enc->avctx = avctx;
+    roq->avctx = avctx;
 
     enc->framesSinceKeyframe = 0;
     if ((avctx->width & 0xf) || (avctx->height & 0xf)) {
@@ -996,30 +1029,30 @@ static av_cold int roq_encode_init(AVCodecContext *avctx)
     if (((avctx->width)&(avctx->width-1))||((avctx->height)&(avctx->height-1)))
         av_log(avctx, AV_LOG_ERROR, "Warning: dimensions not power of two, this is not supported by quake\n");
 
-    enc->width = avctx->width;
-    enc->height = avctx->height;
+    roq->width  = avctx->width;
+    roq->height = avctx->height;
 
     enc->framesSinceKeyframe = 0;
     enc->first_frame = 1;
 
-    enc->last_frame    = av_frame_alloc();
-    enc->current_frame = av_frame_alloc();
-    if (!enc->last_frame || !enc->current_frame)
+    roq->last_frame    = av_frame_alloc();
+    roq->current_frame = av_frame_alloc();
+    if (!roq->last_frame || !roq->current_frame)
         return AVERROR(ENOMEM);
 
     enc->tmpData      = av_malloc(sizeof(RoqTempdata));
 
     enc->this_motion4 =
-        av_mallocz_array((enc->width*enc->height/16), sizeof(motion_vect));
+        av_mallocz_array(roq->width * roq->height / 16, sizeof(motion_vect));
 
     enc->last_motion4 =
-        av_malloc_array ((enc->width*enc->height/16), sizeof(motion_vect));
+        av_malloc_array (roq->width * roq->height / 16, sizeof(motion_vect));
 
     enc->this_motion8 =
-        av_mallocz_array((enc->width*enc->height/64), sizeof(motion_vect));
+        av_mallocz_array(roq->width * roq->height / 64, sizeof(motion_vect));
 
     enc->last_motion8 =
-        av_malloc_array ((enc->width*enc->height/64), sizeof(motion_vect));
+        av_malloc_array (roq->width * roq->height / 64, sizeof(motion_vect));
 
     if (!enc->tmpData || !enc->this_motion4 || !enc->last_motion4 ||
         !enc->this_motion8 || !enc->last_motion8)
@@ -1028,7 +1061,7 @@ static av_cold int roq_encode_init(AVCodecContext *avctx)
     return 0;
 }
 
-static void roq_write_video_info_chunk(RoqContext *enc)
+static void roq_write_video_info_chunk(RoqEncContext *enc)
 {
     /* ROQ info chunk */
     bytestream_put_le16(&enc->out_buf, RoQ_INFO);
@@ -1041,10 +1074,10 @@ static void roq_write_video_info_chunk(RoqContext *enc)
     bytestream_put_byte(&enc->out_buf, 0x00);
 
     /* Width */
-    bytestream_put_le16(&enc->out_buf, enc->width);
+    bytestream_put_le16(&enc->out_buf, enc->common.width);
 
     /* Height */
-    bytestream_put_le16(&enc->out_buf, enc->height);
+    bytestream_put_le16(&enc->out_buf, enc->common.height);
 
     /* Unused in Quake 3, mimics the output of the real encoder */
     bytestream_put_byte(&enc->out_buf, 0x08);
@@ -1056,10 +1089,11 @@ static void roq_write_video_info_chunk(RoqContext *enc)
 static int roq_encode_frame(AVCodecContext *avctx, AVPacket *pkt,
                             const AVFrame *frame, int *got_packet)
 {
-    RoqContext *enc = avctx->priv_data;
+    RoqEncContext *const enc = avctx->priv_data;
+    RoqContext    *const roq = &enc->common;
     int size, ret;
 
-    enc->avctx = avctx;
+    roq->avctx = avctx;
 
     enc->frame_to_enc = frame;
 
@@ -1070,7 +1104,7 @@ static int roq_encode_frame(AVCodecContext *avctx, AVPacket *pkt,
 
     /* 138 bits max per 8x8 block +
      *     256 codebooks*(6 bytes 2x2 + 4 bytes 4x4) + 8 bytes frame header */
-    size = ((enc->width * enc->height / 64) * 138 + 7) / 8 + 256 * (6 + 4) + 8;
+    size = ((roq->width * roq->height / 64) * 138 + 7) / 8 + 256 * (6 + 4) + 8;
     if ((ret = ff_alloc_packet2(avctx, pkt, size, 0)) < 0)
         return ret;
     enc->out_buf = pkt->data;
@@ -1082,8 +1116,8 @@ static int roq_encode_frame(AVCodecContext *avctx, AVPacket *pkt,
     if (enc->first_frame) {
         /* Alloc memory for the reconstruction data (we must know the stride
          for that) */
-        if ((ret = ff_get_buffer(avctx, enc->current_frame, 0)) < 0 ||
-            (ret = ff_get_buffer(avctx, enc->last_frame,    0)) < 0)
+        if ((ret = ff_get_buffer(avctx, roq->current_frame, 0)) < 0 ||
+            (ret = ff_get_buffer(avctx, roq->last_frame,    0)) < 0)
             return ret;
 
         /* Before the first video frame, write a "video info" chunk */
@@ -1105,7 +1139,7 @@ static int roq_encode_frame(AVCodecContext *avctx, AVPacket *pkt,
     return 0;
 }
 
-#define OFFSET(x) offsetof(RoqContext, x)
+#define OFFSET(x) offsetof(RoqEncContext, x)
 #define VE AV_OPT_FLAG_VIDEO_PARAM | AV_OPT_FLAG_ENCODING_PARAM
 static const AVOption options[] = {
     { "quake3_compat", "Whether to respect known limitations in Quake 3 decoder", OFFSET(quake3_compat), AV_OPT_TYPE_BOOL, { .i64 = 1 }, 0, 1, VE },
@@ -1124,7 +1158,7 @@ AVCodec ff_roq_encoder = {
     .long_name            = NULL_IF_CONFIG_SMALL("id RoQ video"),
     .type                 = AVMEDIA_TYPE_VIDEO,
     .id                   = AV_CODEC_ID_ROQ,
-    .priv_data_size       = sizeof(RoqContext),
+    .priv_data_size       = sizeof(RoqEncContext),
     .init                 = roq_encode_init,
     .encode2              = roq_encode_frame,
     .close                = roq_encode_end,