]> git.sesse.net Git - ffmpeg/blobdiff - libavcodec/h264_slice.c
Merge commit '51d8725a6e4c7f989d6f0f38b59cb54a2d72846c'
[ffmpeg] / libavcodec / h264_slice.c
index 559c6a04e4802eaf7ed405bf639af24671cd7fbc..eef28aedc00b921354d6546f497b5aa86d8981d9 100644 (file)
@@ -161,21 +161,32 @@ static void release_unused_pictures(H264Context *h, int remove_current)
     }
 }
 
-static int alloc_scratch_buffers(H264Context *h, int linesize)
+static int alloc_scratch_buffers(H264SliceContext *sl, int linesize)
 {
+    const H264Context *h = sl->h264;
     int alloc_size = FFALIGN(FFABS(linesize) + 32, 32);
 
-    if (h->bipred_scratchpad)
-        return 0;
-
-    h->bipred_scratchpad = av_malloc(16 * 6 * alloc_size);
+    av_fast_malloc(&sl->bipred_scratchpad, &sl->bipred_scratchpad_allocated, 16 * 6 * alloc_size);
     // edge emu needs blocksize + filter length - 1
     // (= 21x21 for  h264)
-    h->edge_emu_buffer = av_mallocz(alloc_size * 2 * 21);
-
-    if (!h->bipred_scratchpad || !h->edge_emu_buffer) {
-        av_freep(&h->bipred_scratchpad);
-        av_freep(&h->edge_emu_buffer);
+    av_fast_malloc(&sl->edge_emu_buffer, &sl->edge_emu_buffer_allocated, alloc_size * 2 * 21);
+
+    av_fast_malloc(&sl->top_borders[0], &sl->top_borders_allocated[0],
+                   h->mb_width * 16 * 3 * sizeof(uint8_t) * 2);
+    av_fast_malloc(&sl->top_borders[1], &sl->top_borders_allocated[1],
+                   h->mb_width * 16 * 3 * sizeof(uint8_t) * 2);
+
+    if (!sl->bipred_scratchpad || !sl->edge_emu_buffer ||
+        !sl->top_borders[0]    || !sl->top_borders[1]) {
+        av_freep(&sl->bipred_scratchpad);
+        av_freep(&sl->edge_emu_buffer);
+        av_freep(&sl->top_borders[0]);
+        av_freep(&sl->top_borders[1]);
+
+        sl->bipred_scratchpad_allocated = 0;
+        sl->edge_emu_buffer_allocated   = 0;
+        sl->top_borders_allocated[0]    = 0;
+        sl->top_borders_allocated[1]    = 0;
         return AVERROR(ENOMEM);
     }
 
@@ -402,8 +413,6 @@ static void clone_tables(H264Context *dst, H264SliceContext *sl,
     dst->DPB                    = src->DPB;
     dst->cur_pic_ptr            = src->cur_pic_ptr;
     dst->cur_pic                = src->cur_pic;
-    dst->bipred_scratchpad      = NULL;
-    dst->edge_emu_buffer        = NULL;
     ff_h264_pred_init(&dst->hpc, src->avctx->codec_id, src->sps.bit_depth_luma,
                       src->sps.chroma_format_idc);
 }
@@ -481,8 +490,6 @@ int ff_h264_update_thread_context(AVCodecContext *dst,
          * the current value */
         h->avctx->bits_per_raw_sample = h->sps.bit_depth_luma;
 
-        av_freep(&h->bipred_scratchpad);
-
         h->width     = h1->width;
         h->height    = h1->height;
         h->mb_height = h1->mb_height;
@@ -531,19 +538,18 @@ int ff_h264_update_thread_context(AVCodecContext *dst,
         for (i = 0; i < MAX_PPS_COUNT; i++)
             av_freep(h->pps_buffers + i);
 
-        av_freep(&h->rbsp_buffer);
         ff_h264_unref_picture(h, &h->last_pic_for_ec);
         memcpy(h, h1, sizeof(H264Context));
 
         memset(h->sps_buffers, 0, sizeof(h->sps_buffers));
         memset(h->pps_buffers, 0, sizeof(h->pps_buffers));
 
-        memset(&h->er, 0, sizeof(h->er));
         memset(&h->cur_pic, 0, sizeof(h->cur_pic));
         memset(&h->last_pic_for_ec, 0, sizeof(h->last_pic_for_ec));
 
         h->slice_ctx = orig_slice_ctx;
 
+        memset(&h->slice_ctx[0].er,         0, sizeof(h->slice_ctx[0].er));
         memset(&h->slice_ctx[0].mb,         0, sizeof(h->slice_ctx[0].mb));
         memset(&h->slice_ctx[0].mb_luma_dc, 0, sizeof(h->slice_ctx[0].mb_luma_dc));
         memset(&h->slice_ctx[0].mb_padding, 0, sizeof(h->slice_ctx[0].mb_padding));
@@ -565,8 +571,6 @@ int ff_h264_update_thread_context(AVCodecContext *dst,
         h->list_counts       = NULL;
         h->mb2b_xy           = NULL;
         h->mb2br_xy          = NULL;
-        h->rbsp_buffer       = NULL;
-        h->rbsp_buffer_size  = 0;
 
         if (h1->context_initialized) {
         h->context_initialized = 0;
@@ -580,16 +584,13 @@ int ff_h264_update_thread_context(AVCodecContext *dst,
             av_log(dst, AV_LOG_ERROR, "Could not allocate memory\n");
             return ret;
         }
-        ret = ff_h264_context_init(h);
+        ret = ff_h264_slice_context_init(h, &h->slice_ctx[0]);
         if (ret < 0) {
             av_log(dst, AV_LOG_ERROR, "context_init() failed.\n");
             return ret;
         }
         }
 
-        h->bipred_scratchpad = NULL;
-        h->edge_emu_buffer   = NULL;
-
         h->thread_context[0] = h;
         h->context_initialized = h1->context_initialized;
     }
@@ -736,16 +737,16 @@ static int h264_frame_start(H264Context *h)
     h->cur_pic_ptr = pic;
     ff_h264_unref_picture(h, &h->cur_pic);
     if (CONFIG_ERROR_RESILIENCE) {
-        ff_h264_set_erpic(&h->er.cur_pic, NULL);
+        ff_h264_set_erpic(&h->slice_ctx[0].er.cur_pic, NULL);
     }
 
     if ((ret = ff_h264_ref_picture(h, &h->cur_pic, h->cur_pic_ptr)) < 0)
         return ret;
 
     if (CONFIG_ERROR_RESILIENCE) {
-        ff_er_frame_start(&h->er);
-        ff_h264_set_erpic(&h->er.last_pic, NULL);
-        ff_h264_set_erpic(&h->er.next_pic, NULL);
+        ff_er_frame_start(&h->slice_ctx[0].er);
+        ff_h264_set_erpic(&h->slice_ctx[0].er.last_pic, NULL);
+        ff_h264_set_erpic(&h->slice_ctx[0].er.next_pic, NULL);
     }
 
     assert(h->linesize && h->uvlinesize);
@@ -776,7 +777,7 @@ static int h264_frame_start(H264Context *h)
     return 0;
 }
 
-static av_always_inline void backup_mb_border(H264Context *h, H264SliceContext *sl,
+static av_always_inline void backup_mb_border(const H264Context *h, H264SliceContext *sl,
                                               uint8_t *src_y,
                                               uint8_t *src_cb, uint8_t *src_cr,
                                               int linesize, int uvlinesize,
@@ -794,8 +795,8 @@ static av_always_inline void backup_mb_border(H264Context *h, H264SliceContext *
 
     if (!simple && FRAME_MBAFF(h)) {
         if (sl->mb_y & 1) {
-            if (!MB_MBAFF(h)) {
-                top_border = h->top_borders[0][sl->mb_x];
+            if (!MB_MBAFF(sl)) {
+                top_border = sl->top_borders[0][sl->mb_x];
                 AV_COPY128(top_border, src_y + 15 * linesize);
                 if (pixel_shift)
                     AV_COPY128(top_border + 16, src_y + 15 * linesize + 16);
@@ -829,13 +830,13 @@ static av_always_inline void backup_mb_border(H264Context *h, H264SliceContext *
                     }
                 }
             }
-        } else if (MB_MBAFF(h)) {
+        } else if (MB_MBAFF(sl)) {
             top_idx = 0;
         } else
             return;
     }
 
-    top_border = h->top_borders[top_idx][sl->mb_x];
+    top_border = sl->top_borders[top_idx][sl->mb_x];
     /* There are two lines saved, the line above the top macroblock
      * of a pair, and the line above the bottom macroblock. */
     AV_COPY128(top_border, src_y + 16 * linesize);
@@ -878,7 +879,7 @@ static av_always_inline void backup_mb_border(H264Context *h, H264SliceContext *
  * @param field  0/1 initialize the weight for interlaced MBAFF
  *                -1 initializes the rest
  */
-static void implicit_weight_table(H264Context *h, H264SliceContext *sl, int field)
+static void implicit_weight_table(const H264Context *h, H264SliceContext *sl, int field)
 {
     int ref0, ref1, i, cur_poc, ref_start, ref_count0, ref_count1;
 
@@ -976,34 +977,6 @@ static void init_scan_tables(H264Context *h)
     }
 }
 
-/**
- * Replicate H264 "master" context to thread contexts.
- */
-static int clone_slice(H264Context *dst, H264Context *src)
-{
-    memcpy(dst->block_offset, src->block_offset, sizeof(dst->block_offset));
-    dst->cur_pic_ptr = src->cur_pic_ptr;
-    dst->cur_pic     = src->cur_pic;
-    dst->linesize    = src->linesize;
-    dst->uvlinesize  = src->uvlinesize;
-    dst->first_field = src->first_field;
-
-    dst->prev_poc_msb          = src->prev_poc_msb;
-    dst->prev_poc_lsb          = src->prev_poc_lsb;
-    dst->prev_frame_num_offset = src->prev_frame_num_offset;
-    dst->prev_frame_num        = src->prev_frame_num;
-    dst->short_ref_count       = src->short_ref_count;
-
-    memcpy(dst->short_ref,        src->short_ref,        sizeof(dst->short_ref));
-    memcpy(dst->long_ref,         src->long_ref,         sizeof(dst->long_ref));
-    memcpy(dst->default_ref_list, src->default_ref_list, sizeof(dst->default_ref_list));
-
-    memcpy(dst->dequant4_coeff,   src->dequant4_coeff,   sizeof(src->dequant4_coeff));
-    memcpy(dst->dequant8_coeff,   src->dequant8_coeff,   sizeof(src->dequant8_coeff));
-
-    return 0;
-}
-
 static enum AVPixelFormat get_pixel_format(H264Context *h, int force_callback)
 {
 #define HWACCEL_MAX (CONFIG_H264_DXVA2_HWACCEL + \
@@ -1197,7 +1170,7 @@ static int h264_slice_header_init(H264Context *h, int reinit)
     h->slice_context_count = nb_slices;
 
     if (!HAVE_THREADS || !(h->avctx->active_thread_type & FF_THREAD_SLICE)) {
-        ret = ff_h264_context_init(h);
+        ret = ff_h264_slice_context_init(h, &h->slice_ctx[0]);
         if (ret < 0) {
             av_log(h->avctx, AV_LOG_ERROR, "context_init() failed.\n");
             goto fail;
@@ -1243,7 +1216,7 @@ static int h264_slice_header_init(H264Context *h, int reinit)
         }
 
         for (i = 0; i < h->slice_context_count; i++)
-            if ((ret = ff_h264_context_init(h->thread_context[i])) < 0) {
+            if ((ret = ff_h264_slice_context_init(h, &h->slice_ctx[i])) < 0) {
                 av_log(h->avctx, AV_LOG_ERROR, "context_init() failed.\n");
                 goto fail;
             }
@@ -1274,12 +1247,10 @@ static enum AVPixelFormat non_j_pixfmt(enum AVPixelFormat a)
  * This will (re)intialize the decoder and call h264_frame_start() as needed.
  *
  * @param h h264context
- * @param h0 h264 master context (differs from 'h' when doing sliced based
- *           parallel decoding)
  *
  * @return 0 if okay, <0 if an error occurred, 1 if decoding must not be multithreaded
  */
-int ff_h264_decode_slice_header(H264Context *h, H264SliceContext *sl, H264Context *h0)
+int ff_h264_decode_slice_header(H264Context *h, H264SliceContext *sl)
 {
     unsigned int first_mb_in_slice;
     unsigned int pps_id;
@@ -1289,7 +1260,7 @@ int ff_h264_decode_slice_header(H264Context *h, H264SliceContext *sl, H264Contex
     int must_reinit;
     int needs_reinit = 0;
     int field_pic_flag, bottom_field_flag;
-    int first_slice = h == h0 && !h0->current_slice;
+    int first_slice = sl == h->slice_ctx && !h->current_slice;
     int frame_num, picture_structure, droppable;
     PPS *pps;
 
@@ -1299,12 +1270,12 @@ int ff_h264_decode_slice_header(H264Context *h, H264SliceContext *sl, H264Contex
     first_mb_in_slice = get_ue_golomb_long(&sl->gb);
 
     if (first_mb_in_slice == 0) { // FIXME better field boundary detection
-        if (h0->current_slice && h->cur_pic_ptr && FIELD_PICTURE(h)) {
+        if (h->current_slice && h->cur_pic_ptr && FIELD_PICTURE(h)) {
             ff_h264_field_end(h, sl, 1);
         }
 
-        h0->current_slice = 0;
-        if (!h0->first_field) {
+        h->current_slice = 0;
+        if (!h->first_field) {
             if (h->cur_pic_ptr && !h->droppable) {
                 ff_thread_report_progress(&h->cur_pic_ptr->tf, INT_MAX,
                                           h->picture_structure == PICT_BOTTOM_FIELD);
@@ -1327,6 +1298,7 @@ int ff_h264_decode_slice_header(H264Context *h, H264SliceContext *sl, H264Contex
         sl->slice_type_fixed = 0;
 
     slice_type = golomb_to_pict_type[slice_type];
+
     sl->slice_type     = slice_type;
     sl->slice_type_nos = slice_type & 3;
 
@@ -1353,33 +1325,33 @@ int ff_h264_decode_slice_header(H264Context *h, H264SliceContext *sl, H264Contex
         av_log(h->avctx, AV_LOG_ERROR, "pps_id %u out of range\n", pps_id);
         return AVERROR_INVALIDDATA;
     }
-    if (!h0->pps_buffers[pps_id]) {
+    if (!h->pps_buffers[pps_id]) {
         av_log(h->avctx, AV_LOG_ERROR,
                "non-existing PPS %u referenced\n",
                pps_id);
         return AVERROR_INVALIDDATA;
     }
-    if (h0->au_pps_id >= 0 && pps_id != h0->au_pps_id) {
+    if (h->au_pps_id >= 0 && pps_id != h->au_pps_id) {
         av_log(h->avctx, AV_LOG_ERROR,
                "PPS change from %d to %d forbidden\n",
-               h0->au_pps_id, pps_id);
+               h->au_pps_id, pps_id);
         return AVERROR_INVALIDDATA;
     }
 
-    pps = h0->pps_buffers[pps_id];
+    pps = h->pps_buffers[pps_id];
 
-    if (!h0->sps_buffers[pps->sps_id]) {
+    if (!h->sps_buffers[pps->sps_id]) {
         av_log(h->avctx, AV_LOG_ERROR,
                "non-existing SPS %u referenced\n",
                h->pps.sps_id);
         return AVERROR_INVALIDDATA;
     }
     if (first_slice)
-        h->pps = *h0->pps_buffers[pps_id];
+        h->pps = *h->pps_buffers[pps_id];
 
     if (pps->sps_id != h->sps.sps_id ||
         pps->sps_id != h->current_sps_id ||
-        h0->sps_buffers[pps->sps_id]->new) {
+        h->sps_buffers[pps->sps_id]->new) {
 
         if (!first_slice) {
             av_log(h->avctx, AV_LOG_ERROR,
@@ -1387,7 +1359,7 @@ int ff_h264_decode_slice_header(H264Context *h, H264SliceContext *sl, H264Contex
             return AVERROR_INVALIDDATA;
         }
 
-        h->sps = *h0->sps_buffers[h->pps.sps_id];
+        h->sps = *h->sps_buffers[h->pps.sps_id];
 
         if (h->mb_width  != h->sps.mb_width ||
             h->mb_height != h->sps.mb_height * (2 - h->sps.frame_mbs_only_flag) ||
@@ -1418,7 +1390,7 @@ int ff_h264_decode_slice_header(H264Context *h, H264SliceContext *sl, H264Contex
                      || h->mb_width  != h->sps.mb_width
                      || h->mb_height != h->sps.mb_height * (2 - h->sps.frame_mbs_only_flag)
                     ));
-    if (non_j_pixfmt(h0->avctx->pix_fmt) != non_j_pixfmt(get_pixel_format(h0, 0)))
+    if (non_j_pixfmt(h->avctx->pix_fmt) != non_j_pixfmt(get_pixel_format(h, 0)))
         must_reinit = 1;
 
     if (first_slice && av_cmp_q(h->sps.sar, h->avctx->sample_aspect_ratio))
@@ -1454,13 +1426,13 @@ int ff_h264_decode_slice_header(H264Context *h, H264SliceContext *sl, H264Contex
 
     if (h->context_initialized &&
         (must_reinit || needs_reinit)) {
-        if (h != h0) {
+        if (sl != h->slice_ctx) {
             av_log(h->avctx, AV_LOG_ERROR,
                    "changing width %d -> %d / height %d -> %d on "
                    "slice %d\n",
                    h->width, h->avctx->coded_width,
                    h->height, h->avctx->coded_height,
-                   h0->current_slice + 1);
+                   h->current_slice + 1);
             return AVERROR_INVALIDDATA;
         }
 
@@ -1482,7 +1454,7 @@ int ff_h264_decode_slice_header(H264Context *h, H264SliceContext *sl, H264Contex
         }
     }
     if (!h->context_initialized) {
-        if (h != h0) {
+        if (sl != h->slice_ctx) {
             av_log(h->avctx, AV_LOG_ERROR,
                    "Cannot (re-)initialize context during parallel decoding.\n");
             return AVERROR_PATCHWELCOME;
@@ -1506,17 +1478,17 @@ int ff_h264_decode_slice_header(H264Context *h, H264SliceContext *sl, H264Contex
 
     frame_num = get_bits(&sl->gb, h->sps.log2_max_frame_num);
     if (!first_slice) {
-        if (h0->frame_num != frame_num) {
+        if (h->frame_num != frame_num) {
             av_log(h->avctx, AV_LOG_ERROR, "Frame num change from %d to %d\n",
-                   h0->frame_num, frame_num);
+                   h->frame_num, frame_num);
             return AVERROR_INVALIDDATA;
         }
     }
 
-    h->mb_mbaff        = 0;
+    sl->mb_mbaff       = 0;
     h->mb_aff_frame    = 0;
-    last_pic_structure = h0->picture_structure;
-    last_pic_droppable = h0->droppable;
+    last_pic_structure = h->picture_structure;
+    last_pic_droppable = h->droppable;
     droppable          = h->nal_ref_idc == 0;
     if (h->sps.frame_mbs_only_flag) {
         picture_structure = PICT_FRAME;
@@ -1535,17 +1507,17 @@ int ff_h264_decode_slice_header(H264Context *h, H264SliceContext *sl, H264Contex
             h->mb_aff_frame      = h->sps.mb_aff;
         }
     }
-    if (h0->current_slice) {
+    if (h->current_slice) {
         if (last_pic_structure != picture_structure ||
             last_pic_droppable != droppable) {
             av_log(h->avctx, AV_LOG_ERROR,
                    "Changing field mode (%d -> %d) between slices is not allowed\n",
                    last_pic_structure, h->picture_structure);
             return AVERROR_INVALIDDATA;
-        } else if (!h0->cur_pic_ptr) {
+        } else if (!h->cur_pic_ptr) {
             av_log(h->avctx, AV_LOG_ERROR,
                    "unset cur_pic_ptr on slice %d\n",
-                   h0->current_slice + 1);
+                   h->current_slice + 1);
             return AVERROR_INVALIDDATA;
         }
     }
@@ -1553,9 +1525,9 @@ int ff_h264_decode_slice_header(H264Context *h, H264SliceContext *sl, H264Contex
     h->picture_structure = picture_structure;
     h->droppable         = droppable;
     h->frame_num         = frame_num;
-    h->mb_field_decoding_flag = picture_structure != PICT_FRAME;
+    sl->mb_field_decoding_flag = picture_structure != PICT_FRAME;
 
-    if (h0->current_slice == 0) {
+    if (h->current_slice == 0) {
         /* Shorten frame num gaps so we don't have to allocate reference
          * frames just to throw them away */
         if (h->frame_num != h->prev_frame_num) {
@@ -1579,14 +1551,14 @@ int ff_h264_decode_slice_header(H264Context *h, H264SliceContext *sl, H264Contex
          * decode frames as "finished".
          * We have to do that before the "dummy" in-between frame allocation,
          * since that can modify h->cur_pic_ptr. */
-        if (h0->first_field) {
-            assert(h0->cur_pic_ptr);
-            assert(h0->cur_pic_ptr->f.buf[0]);
-            assert(h0->cur_pic_ptr->reference != DELAYED_PIC_REF);
+        if (h->first_field) {
+            assert(h->cur_pic_ptr);
+            assert(h->cur_pic_ptr->f.buf[0]);
+            assert(h->cur_pic_ptr->reference != DELAYED_PIC_REF);
 
             /* Mark old field/frame as completed */
-            if (h0->cur_pic_ptr->tf.owner == h0->avctx) {
-                ff_thread_report_progress(&h0->cur_pic_ptr->tf, INT_MAX,
+            if (h->cur_pic_ptr->tf.owner == h->avctx) {
+                ff_thread_report_progress(&h->cur_pic_ptr->tf, INT_MAX,
                                           last_pic_structure == PICT_BOTTOM_FIELD);
             }
 
@@ -1595,17 +1567,17 @@ int ff_h264_decode_slice_header(H264Context *h, H264SliceContext *sl, H264Contex
                 /* Previous field is unmatched. Don't display it, but let it
                  * remain for reference if marked as such. */
                 if (last_pic_structure != PICT_FRAME) {
-                    ff_thread_report_progress(&h0->cur_pic_ptr->tf, INT_MAX,
+                    ff_thread_report_progress(&h->cur_pic_ptr->tf, INT_MAX,
                                               last_pic_structure == PICT_TOP_FIELD);
                 }
             } else {
-                if (h0->cur_pic_ptr->frame_num != h->frame_num) {
+                if (h->cur_pic_ptr->frame_num != h->frame_num) {
                     /* This and previous field were reference, but had
                      * different frame_nums. Consider this field first in
                      * pair. Throw away previous field except for reference
                      * purposes. */
                     if (last_pic_structure != PICT_FRAME) {
-                        ff_thread_report_progress(&h0->cur_pic_ptr->tf, INT_MAX,
+                        ff_thread_report_progress(&h->cur_pic_ptr->tf, INT_MAX,
                                                   last_pic_structure == PICT_TOP_FIELD);
                     }
                 } else {
@@ -1631,7 +1603,7 @@ int ff_h264_decode_slice_header(H264Context *h, H264SliceContext *sl, H264Contex
             }
         }
 
-        while (h->frame_num != h->prev_frame_num && !h0->first_field &&
+        while (h->frame_num != h->prev_frame_num && !h->first_field &&
                h->frame_num != (h->prev_frame_num + 1) % (1 << h->sps.log2_max_frame_num)) {
             H264Picture *prev = h->short_ref_count ? h->short_ref[0] : NULL;
             av_log(h->avctx, AV_LOG_DEBUG, "Frame num gap %d %d\n",
@@ -1641,7 +1613,7 @@ int ff_h264_decode_slice_header(H264Context *h, H264SliceContext *sl, H264Contex
                     h->last_pocs[i] = INT_MIN;
             ret = h264_frame_start(h);
             if (ret < 0) {
-                h0->first_field = 0;
+                h->first_field = 0;
                 return ret;
             }
 
@@ -1682,41 +1654,41 @@ int ff_h264_decode_slice_header(H264Context *h, H264SliceContext *sl, H264Contex
         /* See if we have a decoded first field looking for a pair...
          * We're using that to see whether to continue decoding in that
          * frame, or to allocate a new one. */
-        if (h0->first_field) {
-            assert(h0->cur_pic_ptr);
-            assert(h0->cur_pic_ptr->f.buf[0]);
-            assert(h0->cur_pic_ptr->reference != DELAYED_PIC_REF);
+        if (h->first_field) {
+            assert(h->cur_pic_ptr);
+            assert(h->cur_pic_ptr->f.buf[0]);
+            assert(h->cur_pic_ptr->reference != DELAYED_PIC_REF);
 
             /* figure out if we have a complementary field pair */
             if (!FIELD_PICTURE(h) || h->picture_structure == last_pic_structure) {
                 /* Previous field is unmatched. Don't display it, but let it
                  * remain for reference if marked as such. */
-                h0->missing_fields ++;
-                h0->cur_pic_ptr = NULL;
-                h0->first_field = FIELD_PICTURE(h);
+                h->missing_fields ++;
+                h->cur_pic_ptr = NULL;
+                h->first_field = FIELD_PICTURE(h);
             } else {
-                h0->missing_fields = 0;
-                if (h0->cur_pic_ptr->frame_num != h->frame_num) {
-                    ff_thread_report_progress(&h0->cur_pic_ptr->tf, INT_MAX,
-                                              h0->picture_structure==PICT_BOTTOM_FIELD);
+                h->missing_fields = 0;
+                if (h->cur_pic_ptr->frame_num != h->frame_num) {
+                    ff_thread_report_progress(&h->cur_pic_ptr->tf, INT_MAX,
+                                              h->picture_structure==PICT_BOTTOM_FIELD);
                     /* This and the previous field had different frame_nums.
                      * Consider this field first in pair. Throw away previous
                      * one except for reference purposes. */
-                    h0->first_field = 1;
-                    h0->cur_pic_ptr = NULL;
+                    h->first_field = 1;
+                    h->cur_pic_ptr = NULL;
                 } else {
                     /* Second field in complementary pair */
-                    h0->first_field = 0;
+                    h->first_field = 0;
                 }
             }
         } else {
             /* Frame or first field in a potentially complementary pair */
-            h0->first_field = FIELD_PICTURE(h);
+            h->first_field = FIELD_PICTURE(h);
         }
 
-        if (!FIELD_PICTURE(h) || h0->first_field) {
+        if (!FIELD_PICTURE(h) || h->first_field) {
             if (h264_frame_start(h) < 0) {
-                h0->first_field = 0;
+                h->first_field = 0;
                 return AVERROR_INVALIDDATA;
             }
         } else {
@@ -1731,19 +1703,9 @@ int ff_h264_decode_slice_header(H264Context *h, H264SliceContext *sl, H264Contex
             memset(h->slice_table, -1,
                 (h->mb_height * h->mb_stride - 1) * sizeof(*h->slice_table));
         }
-        h0->last_slice_type = -1;
+        h->last_slice_type = -1;
     }
-    if (h != h0 && (ret = clone_slice(h, h0)) < 0)
-        return ret;
 
-    /* can't be in alloc_tables because linesize isn't known there.
-     * FIXME: redo bipred weight to not require extra buffer? */
-    for (i = 0; i < h->slice_context_count; i++)
-        if (h->thread_context[i]) {
-            ret = alloc_scratch_buffers(h->thread_context[i], h->linesize);
-            if (ret < 0)
-                return ret;
-        }
 
     h->cur_pic_ptr->frame_num = h->frame_num; // FIXME frame_num cleanup
 
@@ -1795,9 +1757,9 @@ int ff_h264_decode_slice_header(H264Context *h, H264SliceContext *sl, H264Contex
         return ret;
 
     if (slice_type != AV_PICTURE_TYPE_I &&
-        (h0->current_slice == 0 ||
-         slice_type != h0->last_slice_type ||
-         memcmp(h0->last_ref_count, sl->ref_count, sizeof(sl->ref_count)))) {
+        (h->current_slice == 0 ||
+         slice_type != h->last_slice_type ||
+         memcmp(h->last_ref_count, sl->ref_count, sizeof(sl->ref_count)))) {
 
         ff_h264_fill_default_ref_list(h, sl);
     }
@@ -1831,9 +1793,9 @@ int ff_h264_decode_slice_header(H264Context *h, H264SliceContext *sl, H264Contex
     // further down the line. This may break decoding if the first slice is
     // corrupt, thus we only do this if frame-mt is enabled.
     if (h->nal_ref_idc) {
-        ret = ff_h264_decode_ref_pic_marking(h0, &sl->gb,
+        ret = ff_h264_decode_ref_pic_marking(h, &sl->gb,
                                              !(h->avctx->active_thread_type & FF_THREAD_FRAME) ||
-                                             h0->current_slice == 0);
+                                             h->current_slice == 0);
         if (ret < 0 && (h->avctx->err_recognition & AV_EF_EXPLODE))
             return AVERROR_INVALIDDATA;
     }
@@ -1916,22 +1878,22 @@ int ff_h264_decode_slice_header(H264Context *h, H264SliceContext *sl, H264Contex
          h->nal_ref_idc == 0))
         sl->deblocking_filter = 0;
 
-    if (sl->deblocking_filter == 1 && h0->max_contexts > 1) {
+    if (sl->deblocking_filter == 1 && h->max_contexts > 1) {
         if (h->avctx->flags2 & CODEC_FLAG2_FAST) {
             /* Cheat slightly for speed:
              * Do not bother to deblock across slices. */
             sl->deblocking_filter = 2;
         } else {
-            h0->max_contexts = 1;
-            if (!h0->single_decode_warning) {
+            h->max_contexts = 1;
+            if (!h->single_decode_warning) {
                 av_log(h->avctx, AV_LOG_INFO,
                        "Cannot parallelize slice decoding with deblocking filter type 1, decoding such frames in sequential order\n"
                        "To parallelize slice decoding you need video encoded with disable_deblocking_filter_idc set to 2 (deblock only edges that do not cross slices).\n"
                        "Setting the flags2 libavcodec option to +fast (-flags2 +fast) will disable deblocking across slices and enable parallel slice decoding "
                        "but will generate non-standard-compliant output.\n");
-                h0->single_decode_warning = 1;
+                h->single_decode_warning = 1;
             }
-            if (h != h0) {
+            if (sl != h->slice_ctx) {
                 av_log(h->avctx, AV_LOG_ERROR,
                        "Deblocking switched inside frame.\n");
                 return SLICE_SINGLETHREAD;
@@ -1945,14 +1907,14 @@ int ff_h264_decode_slice_header(H264Context *h, H264SliceContext *sl, H264Contex
                           h->pps.chroma_qp_index_offset[1]) +
                    6 * (h->sps.bit_depth_luma - 8);
 
-    h0->last_slice_type = slice_type;
-    memcpy(h0->last_ref_count, sl->ref_count, sizeof(h0->last_ref_count));
-    sl->slice_num       = ++h0->current_slice;
+    h->last_slice_type = slice_type;
+    memcpy(h->last_ref_count, sl->ref_count, sizeof(h->last_ref_count));
+    sl->slice_num       = ++h->current_slice;
 
     if (sl->slice_num)
-        h0->slice_row[(sl->slice_num-1)&(MAX_SLICES-1)]= sl->resync_mb_y;
-    if (   h0->slice_row[sl->slice_num&(MAX_SLICES-1)] + 3 >= sl->resync_mb_y
-        && h0->slice_row[sl->slice_num&(MAX_SLICES-1)] <= sl->resync_mb_y
+        h->slice_row[(sl->slice_num-1)&(MAX_SLICES-1)]= sl->resync_mb_y;
+    if (   h->slice_row[sl->slice_num&(MAX_SLICES-1)] + 3 >= sl->resync_mb_y
+        && h->slice_row[sl->slice_num&(MAX_SLICES-1)] <= sl->resync_mb_y
         && sl->slice_num >= MAX_SLICES) {
         //in case of ASO this check needs to be updated depending on how we decide to assign slice numbers in this case
         av_log(h->avctx, AV_LOG_WARNING, "Possibly too many slices (%d >= %d), increase MAX_SLICES and recompile if there are artifacts\n", sl->slice_num, MAX_SLICES);
@@ -1991,9 +1953,9 @@ int ff_h264_decode_slice_header(H264Context *h, H264SliceContext *sl, H264Contex
                              (sl->ref_list[j][i].reference & 3);
     }
 
-    h0->au_pps_id = pps_id;
+    h->au_pps_id = pps_id;
     h->sps.new =
-    h0->sps_buffers[h->pps.sps_id]->new = 0;
+    h->sps_buffers[h->pps.sps_id]->new = 0;
     h->current_sps_id = h->pps.sps_id;
 
     if (h->avctx->debug & FF_DEBUG_PICT_INFO) {
@@ -2038,7 +2000,7 @@ int ff_h264_get_slice_type(const H264SliceContext *sl)
     }
 }
 
-static av_always_inline void fill_filter_caches_inter(H264Context *h,
+static av_always_inline void fill_filter_caches_inter(const H264Context *h,
                                                       H264SliceContext *sl,
                                                       int mb_type, int top_xy,
                                                       int left_xy[LEFT_MBS],
@@ -2053,7 +2015,7 @@ static av_always_inline void fill_filter_caches_inter(H264Context *h,
         if (USES_LIST(top_type, list)) {
             const int b_xy  = h->mb2b_xy[top_xy] + 3 * b_stride;
             const int b8_xy = 4 * top_xy + 2;
-            int (*ref2frm)[64] = (void*)(sl->ref2frm[h->slice_table[top_xy] & (MAX_SLICES - 1)][0] + (MB_MBAFF(h) ? 20 : 2));
+            int (*ref2frm)[64] = (void*)(sl->ref2frm[h->slice_table[top_xy] & (MAX_SLICES - 1)][0] + (MB_MBAFF(sl) ? 20 : 2));
             AV_COPY128(mv_dst - 1 * 8, h->cur_pic.motion_val[list][b_xy + 0]);
             ref_cache[0 - 1 * 8] =
             ref_cache[1 - 1 * 8] = ref2frm[list][h->cur_pic.ref_index[list][b8_xy + 0]];
@@ -2068,7 +2030,7 @@ static av_always_inline void fill_filter_caches_inter(H264Context *h,
             if (USES_LIST(left_type[LTOP], list)) {
                 const int b_xy  = h->mb2b_xy[left_xy[LTOP]] + 3;
                 const int b8_xy = 4 * left_xy[LTOP] + 1;
-                int (*ref2frm)[64] =(void*)( sl->ref2frm[h->slice_table[left_xy[LTOP]] & (MAX_SLICES - 1)][0] + (MB_MBAFF(h) ? 20 : 2));
+                int (*ref2frm)[64] =(void*)( sl->ref2frm[h->slice_table[left_xy[LTOP]] & (MAX_SLICES - 1)][0] + (MB_MBAFF(sl) ? 20 : 2));
                 AV_COPY32(mv_dst - 1 +  0, h->cur_pic.motion_val[list][b_xy + b_stride * 0]);
                 AV_COPY32(mv_dst - 1 +  8, h->cur_pic.motion_val[list][b_xy + b_stride * 1]);
                 AV_COPY32(mv_dst - 1 + 16, h->cur_pic.motion_val[list][b_xy + b_stride * 2]);
@@ -2101,7 +2063,7 @@ static av_always_inline void fill_filter_caches_inter(H264Context *h,
 
     {
         int8_t *ref = &h->cur_pic.ref_index[list][4 * mb_xy];
-        int (*ref2frm)[64] = (void*)(sl->ref2frm[sl->slice_num & (MAX_SLICES - 1)][0] + (MB_MBAFF(h) ? 20 : 2));
+        int (*ref2frm)[64] = (void*)(sl->ref2frm[sl->slice_num & (MAX_SLICES - 1)][0] + (MB_MBAFF(sl) ? 20 : 2));
         uint32_t ref01 = (pack16to32(ref2frm[list][ref[0]], ref2frm[list][ref[1]]) & 0x00FF00FF) * 0x0101;
         uint32_t ref23 = (pack16to32(ref2frm[list][ref[2]], ref2frm[list][ref[3]]) & 0x00FF00FF) * 0x0101;
         AV_WN32A(&ref_cache[0 * 8], ref01);
@@ -2123,7 +2085,7 @@ static av_always_inline void fill_filter_caches_inter(H264Context *h,
  *
  * @return non zero if the loop filter can be skipped
  */
-static int fill_filter_caches(H264Context *h, H264SliceContext *sl, int mb_type)
+static int fill_filter_caches(const H264Context *h, H264SliceContext *sl, int mb_type)
 {
     const int mb_xy = sl->mb_xy;
     int top_xy, left_xy[LEFT_MBS];
@@ -2131,7 +2093,7 @@ static int fill_filter_caches(H264Context *h, H264SliceContext *sl, int mb_type)
     uint8_t *nnz;
     uint8_t *nnz_cache;
 
-    top_xy = mb_xy - (h->mb_stride << MB_FIELD(h));
+    top_xy = mb_xy - (h->mb_stride << MB_FIELD(sl));
 
     /* Wow, what a mess, why didn't they simplify the interlacing & intra
      * stuff, I can't imagine that these complex rules are worth it. */
@@ -2268,7 +2230,7 @@ static int fill_filter_caches(H264Context *h, H264SliceContext *sl, int mb_type)
     return 0;
 }
 
-static void loop_filter(H264Context *h, H264SliceContext *sl, int start_x, int end_x)
+static void loop_filter(const H264Context *h, H264SliceContext *sl, int start_x, int end_x)
 {
     uint8_t *dest_y, *dest_cb, *dest_cr;
     int linesize, uvlinesize, mb_x, mb_y;
@@ -2287,8 +2249,8 @@ static void loop_filter(H264Context *h, H264SliceContext *sl, int start_x, int e
                 sl->list_count = h->list_counts[mb_xy];
 
                 if (FRAME_MBAFF(h))
-                    h->mb_mbaff               =
-                    h->mb_field_decoding_flag = !!IS_INTERLACED(mb_type);
+                    sl->mb_mbaff               =
+                    sl->mb_field_decoding_flag = !!IS_INTERLACED(mb_type);
 
                 sl->mb_x = mb_x;
                 sl->mb_y = mb_y;
@@ -2302,7 +2264,7 @@ static void loop_filter(H264Context *h, H264SliceContext *sl, int start_x, int e
                           mb_y * h->uvlinesize * block_h;
                 // FIXME simplify above
 
-                if (MB_FIELD(h)) {
+                if (MB_FIELD(sl)) {
                     linesize   = sl->mb_linesize   = h->linesize   * 2;
                     uvlinesize = sl->mb_uvlinesize = h->uvlinesize * 2;
                     if (mb_y & 1) { // FIXME move out of this function?
@@ -2337,20 +2299,20 @@ static void loop_filter(H264Context *h, H264SliceContext *sl, int start_x, int e
     sl->chroma_qp[1] = get_chroma_qp(h, 1, sl->qscale);
 }
 
-static void predict_field_decoding_flag(H264Context *h, H264SliceContext *sl)
+static void predict_field_decoding_flag(const H264Context *h, H264SliceContext *sl)
 {
     const int mb_xy = sl->mb_x + sl->mb_y * h->mb_stride;
     int mb_type     = (h->slice_table[mb_xy - 1] == sl->slice_num) ?
                       h->cur_pic.mb_type[mb_xy - 1] :
                       (h->slice_table[mb_xy - h->mb_stride] == sl->slice_num) ?
                       h->cur_pic.mb_type[mb_xy - h->mb_stride] : 0;
-    h->mb_mbaff     = h->mb_field_decoding_flag = IS_INTERLACED(mb_type) ? 1 : 0;
+    sl->mb_mbaff    = sl->mb_field_decoding_flag = IS_INTERLACED(mb_type) ? 1 : 0;
 }
 
 /**
  * Draw edges and report progress for the last MB row.
  */
-static void decode_finish_row(H264Context *h, H264SliceContext *sl)
+static void decode_finish_row(const H264Context *h, H264SliceContext *sl)
 {
     int top            = 16 * (sl->mb_y      >> FIELD_PICTURE(h));
     int pic_height     = 16 *  h->mb_height >> FIELD_PICTURE(h);
@@ -2374,19 +2336,19 @@ static void decode_finish_row(H264Context *h, H264SliceContext *sl)
 
     ff_h264_draw_horiz_band(h, sl, top, height);
 
-    if (h->droppable || h->er.error_occurred)
+    if (h->droppable || sl->er.error_occurred)
         return;
 
     ff_thread_report_progress(&h->cur_pic_ptr->tf, top + height - 1,
                               h->picture_structure == PICT_BOTTOM_FIELD);
 }
 
-static void er_add_slice(H264Context *h, H264SliceContext *sl,
+static void er_add_slice(H264SliceContext *sl,
                          int startx, int starty,
                          int endx, int endy, int status)
 {
     if (CONFIG_ERROR_RESILIENCE) {
-        ERContext *er = &h->er;
+        ERContext *er = &sl->er;
 
         ff_er_add_slice(er, startx, starty, endx, endy, status);
     }
@@ -2395,8 +2357,13 @@ static void er_add_slice(H264Context *h, H264SliceContext *sl,
 static int decode_slice(struct AVCodecContext *avctx, void *arg)
 {
     H264SliceContext *sl = arg;
-    H264Context       *h = sl->h264;
+    const H264Context *h = avctx->priv_data;
     int lf_x_start = sl->mb_x;
+    int ret;
+
+    ret = alloc_scratch_buffers(sl, h->linesize);
+    if (ret < 0)
+        return ret;
 
     sl->mb_skip_run = -1;
 
@@ -2406,13 +2373,13 @@ static int decode_slice(struct AVCodecContext *avctx, void *arg)
                      avctx->codec_id != AV_CODEC_ID_H264 ||
                      (CONFIG_GRAY && (h->flags & CODEC_FLAG_GRAY));
 
-    if (!(h->avctx->active_thread_type & FF_THREAD_SLICE) && h->picture_structure == PICT_FRAME && h->er.error_status_table) {
+    if (!(h->avctx->active_thread_type & FF_THREAD_SLICE) && h->picture_structure == PICT_FRAME && sl->er.error_status_table) {
         const int start_i  = av_clip(sl->resync_mb_x + sl->resync_mb_y * h->mb_width, 0, h->mb_num - 1);
         if (start_i) {
-            int prev_status = h->er.error_status_table[h->er.mb_index2xy[start_i - 1]];
+            int prev_status = sl->er.error_status_table[sl->er.mb_index2xy[start_i - 1]];
             prev_status &= ~ VP_START;
             if (prev_status != (ER_MV_END | ER_DC_END | ER_AC_END))
-                h->er.error_occurred = 1;
+                sl->er.error_occurred = 1;
         }
     }
 
@@ -2450,7 +2417,7 @@ static int decode_slice(struct AVCodecContext *avctx, void *arg)
 
             if ((h->workaround_bugs & FF_BUG_TRUNCATED) &&
                 sl->cabac.bytestream > sl->cabac.bytestream_end + 2) {
-                er_add_slice(h, sl, sl->resync_mb_x, sl->resync_mb_y, sl->mb_x - 1,
+                er_add_slice(sl, sl->resync_mb_x, sl->resync_mb_y, sl->mb_x - 1,
                              sl->mb_y, ER_MB_END);
                 if (sl->mb_x >= lf_x_start)
                     loop_filter(h, sl, lf_x_start, sl->mb_x + 1);
@@ -2463,7 +2430,7 @@ static int decode_slice(struct AVCodecContext *avctx, void *arg)
                        "error while decoding MB %d %d, bytestream %"PTRDIFF_SPECIFIER"\n",
                        sl->mb_x, sl->mb_y,
                        sl->cabac.bytestream_end - sl->cabac.bytestream);
-                er_add_slice(h, sl, sl->resync_mb_x, sl->resync_mb_y, sl->mb_x,
+                er_add_slice(sl, sl->resync_mb_x, sl->resync_mb_y, sl->mb_x,
                              sl->mb_y, ER_MB_ERROR);
                 return AVERROR_INVALIDDATA;
             }
@@ -2483,7 +2450,7 @@ static int decode_slice(struct AVCodecContext *avctx, void *arg)
             if (eos || sl->mb_y >= h->mb_height) {
                 tprintf(h->avctx, "slice end %d %d\n",
                         get_bits_count(&sl->gb), sl->gb.size_in_bits);
-                er_add_slice(h, sl, sl->resync_mb_x, sl->resync_mb_y, sl->mb_x - 1,
+                er_add_slice(sl, sl->resync_mb_x, sl->resync_mb_y, sl->mb_x - 1,
                              sl->mb_y, ER_MB_END);
                 if (sl->mb_x > lf_x_start)
                     loop_filter(h, sl, lf_x_start, sl->mb_x);
@@ -2510,7 +2477,7 @@ static int decode_slice(struct AVCodecContext *avctx, void *arg)
             if (ret < 0) {
                 av_log(h->avctx, AV_LOG_ERROR,
                        "error while decoding MB %d %d\n", sl->mb_x, sl->mb_y);
-                er_add_slice(h, sl, sl->resync_mb_x, sl->resync_mb_y, sl->mb_x,
+                er_add_slice(sl, sl->resync_mb_x, sl->resync_mb_y, sl->mb_x,
                              sl->mb_y, ER_MB_ERROR);
                 return ret;
             }
@@ -2531,12 +2498,12 @@ static int decode_slice(struct AVCodecContext *avctx, void *arg)
 
                     if (   get_bits_left(&sl->gb) == 0
                         || get_bits_left(&sl->gb) > 0 && !(h->avctx->err_recognition & AV_EF_AGGRESSIVE)) {
-                        er_add_slice(h, sl, sl->resync_mb_x, sl->resync_mb_y,
+                        er_add_slice(sl, sl->resync_mb_x, sl->resync_mb_y,
                                      sl->mb_x - 1, sl->mb_y, ER_MB_END);
 
                         return 0;
                     } else {
-                        er_add_slice(h, sl, sl->resync_mb_x, sl->resync_mb_y,
+                        er_add_slice(sl, sl->resync_mb_x, sl->resync_mb_y,
                                      sl->mb_x, sl->mb_y, ER_MB_END);
 
                         return AVERROR_INVALIDDATA;
@@ -2549,14 +2516,14 @@ static int decode_slice(struct AVCodecContext *avctx, void *arg)
                         get_bits_count(&sl->gb), sl->gb.size_in_bits);
 
                 if (get_bits_left(&sl->gb) == 0) {
-                    er_add_slice(h, sl, sl->resync_mb_x, sl->resync_mb_y,
+                    er_add_slice(sl, sl->resync_mb_x, sl->resync_mb_y,
                                  sl->mb_x - 1, sl->mb_y, ER_MB_END);
                     if (sl->mb_x > lf_x_start)
                         loop_filter(h, sl, lf_x_start, sl->mb_x);
 
                     return 0;
                 } else {
-                    er_add_slice(h, sl, sl->resync_mb_x, sl->resync_mb_y, sl->mb_x,
+                    er_add_slice(sl, sl->resync_mb_x, sl->resync_mb_y, sl->mb_x,
                                  sl->mb_y, ER_MB_ERROR);
 
                     return AVERROR_INVALIDDATA;
@@ -2575,7 +2542,6 @@ static int decode_slice(struct AVCodecContext *avctx, void *arg)
 int ff_h264_execute_decode_slices(H264Context *h, unsigned context_count)
 {
     AVCodecContext *const avctx = h->avctx;
-    H264Context *hx;
     H264SliceContext *sl;
     int i;
 
@@ -2591,25 +2557,21 @@ int ff_h264_execute_decode_slices(H264Context *h, unsigned context_count)
     } else {
         av_assert0(context_count > 0);
         for (i = 1; i < context_count; i++) {
-            hx                 = h->thread_context[i];
+            sl                 = &h->slice_ctx[i];
             if (CONFIG_ERROR_RESILIENCE) {
-                hx->er.error_count = 0;
+                sl->er.error_count = 0;
             }
-            hx->x264_build     = h->x264_build;
         }
 
         avctx->execute(avctx, decode_slice, h->slice_ctx,
                        NULL, context_count, sizeof(h->slice_ctx[0]));
 
         /* pull back stuff from slices to master context */
-        hx                   = h->thread_context[context_count - 1];
         sl                   = &h->slice_ctx[context_count - 1];
         h->mb_y              = sl->mb_y;
-        h->droppable         = hx->droppable;
-        h->picture_structure = hx->picture_structure;
         if (CONFIG_ERROR_RESILIENCE) {
             for (i = 1; i < context_count; i++)
-                h->er.error_count += h->thread_context[i]->er.error_count;
+                h->slice_ctx[0].er.error_count += h->slice_ctx[i].er.error_count;
         }
     }