h264: use the main H264Context as the parent for all slice contexts

There is now no need to have per-slice copies of the H264Context.

libavcodec/h264.c

@@ -655,7 +655,7 @@ av_cold int ff_h264_decode_init(AVCodecContext *avctx)
 
     h->thread_context[0] = h;
     for (i = 0; i < h->nb_slice_ctx; i++)
-        h->slice_ctx[i].h264 = h->thread_context[0];
+        h->slice_ctx[i].h264 = h;
 
     h->outputed_poc      = h->next_outputed_poc = INT_MIN;
     for (i = 0; i < MAX_DELAYED_PIC_COUNT; i++)
@@ -1422,7 +1422,6 @@ static int decode_nal_units(H264Context *h, const uint8_t *buf, int buf_size,
                             int parse_extradata)
 {
     AVCodecContext *const avctx = h->avctx;
-    H264Context *hx; ///< thread context
     H264SliceContext *sl;
     int buf_index;
     unsigned context_count;
@@ -1468,10 +1467,9 @@ static int decode_nal_units(H264Context *h, const uint8_t *buf, int buf_size,
                     continue;
             }
 
-            hx = h->thread_context[context_count];
             sl = &h->slice_ctx[context_count];
 
-            ptr = ff_h264_decode_nal(hx, sl, buf + buf_index, &dst_length,
+            ptr = ff_h264_decode_nal(h, sl, buf + buf_index, &dst_length,
                                      &consumed, next_avc - buf_index);
             if (!ptr || dst_length < 0) {
                 ret = -1;
@@ -1484,7 +1482,7 @@ static int decode_nal_units(H264Context *h, const uint8_t *buf, int buf_size,
             if (h->avctx->debug & FF_DEBUG_STARTCODE)
                 av_log(h->avctx, AV_LOG_DEBUG,
                        "NAL %d at %d/%d length %d\n",
-                       hx->nal_unit_type, buf_index, buf_size, dst_length);
+                       h->nal_unit_type, buf_index, buf_size, dst_length);
 
             if (h->is_avc && (nalsize != consumed) && nalsize)
                 av_log(h->avctx, AV_LOG_DEBUG,
@@ -1505,17 +1503,17 @@ again:
              * with frame-mt */
             if (parse_extradata && HAVE_THREADS &&
                 (h->avctx->active_thread_type & FF_THREAD_FRAME) &&
-                (hx->nal_unit_type != NAL_PPS &&
-                 hx->nal_unit_type != NAL_SPS)) {
-                if (hx->nal_unit_type < NAL_AUD ||
-                    hx->nal_unit_type > NAL_AUXILIARY_SLICE)
+                (h->nal_unit_type != NAL_PPS &&
+                 h->nal_unit_type != NAL_SPS)) {
+                if (h->nal_unit_type < NAL_AUD ||
+                    h->nal_unit_type > NAL_AUXILIARY_SLICE)
                     av_log(avctx, AV_LOG_INFO,
                            "Ignoring NAL unit %d during extradata parsing\n",
-                           hx->nal_unit_type);
-                hx->nal_unit_type = NAL_FF_IGNORE;
+                           h->nal_unit_type);
+                h->nal_unit_type = NAL_FF_IGNORE;
             }
             err = 0;
-            switch (hx->nal_unit_type) {
+            switch (h->nal_unit_type) {
             case NAL_IDR_SLICE:
                 if (h->nal_unit_type != NAL_IDR_SLICE) {
                     av_log(h->avctx, AV_LOG_ERROR,
@@ -1527,7 +1525,7 @@ again:
             case NAL_SLICE:
                 init_get_bits(&sl->gb, ptr, bit_length);
 
-                if ((err = ff_h264_decode_slice_header(hx, sl, h)))
+                if ((err = ff_h264_decode_slice_header(h, sl)))
                     break;
 
                 if (h->sei_recovery_frame_cnt >= 0 && h->recovery_frame < 0) {
@@ -1536,17 +1534,17 @@ again:
                 }
 
                 h->cur_pic_ptr->f.key_frame |=
-                    (hx->nal_unit_type == NAL_IDR_SLICE) ||
+                    (h->nal_unit_type == NAL_IDR_SLICE) ||
                     (h->sei_recovery_frame_cnt >= 0);
 
-                if (hx->nal_unit_type == NAL_IDR_SLICE ||
+                if (h->nal_unit_type == NAL_IDR_SLICE ||
                     h->recovery_frame == h->frame_num) {
                     h->recovery_frame         = -1;
                     h->cur_pic_ptr->recovered = 1;
                 }
                 // If we have an IDR, all frames after it in decoded order are
                 // "recovered".
-                if (hx->nal_unit_type == NAL_IDR_SLICE)
+                if (h->nal_unit_type == NAL_IDR_SLICE)
                     h->frame_recovered |= FRAME_RECOVERED_IDR;
                 h->cur_pic_ptr->recovered |= !!(h->frame_recovered & FRAME_RECOVERED_IDR);
 
@@ -1561,7 +1559,7 @@ again:
 
                 if (sl->redundant_pic_count == 0 &&
                     (avctx->skip_frame < AVDISCARD_NONREF ||
-                     hx->nal_ref_idc) &&
+                     h->nal_ref_idc) &&
                     (avctx->skip_frame < AVDISCARD_BIDIR  ||
                      sl->slice_type_nos != AV_PICTURE_TYPE_B) &&
                     (avctx->skip_frame < AVDISCARD_NONKEY ||
@@ -1623,7 +1621,7 @@ again:
                 break;
             default:
                 av_log(avctx, AV_LOG_DEBUG, "Unknown NAL code: %d (%d bits)\n",
-                       hx->nal_unit_type, bit_length);
+                       h->nal_unit_type, bit_length);
             }
 
             if (context_count == h->max_contexts) {
@@ -1637,13 +1635,9 @@ again:
                 av_log(h->avctx, AV_LOG_ERROR, "decode_slice_header error\n");
                 sl->ref_count[0] = sl->ref_count[1] = sl->list_count = 0;
             } else if (err == 1) {
-                /* Slice could not be decoded in parallel mode, copy down
-                 * NAL unit stuff to context 0 and restart. Note that
-                 * rbsp_buffer is not transferred, but since we no longer
+                /* Slice could not be decoded in parallel mode, restart. Note
+                 * that rbsp_buffer is not transferred, but since we no longer
                  * run in parallel mode this should not be an issue. */
-                h->nal_unit_type = hx->nal_unit_type;
-                h->nal_ref_idc   = hx->nal_ref_idc;
-                hx               = h;
                 sl               = &h->slice_ctx[0];
                 goto again;
             }

libavcodec/h264.h

@@ -1070,7 +1070,7 @@ int ff_init_poc(H264Context *h, int pic_field_poc[2], int *pic_poc);
 int ff_pred_weight_table(H264Context *h, H264SliceContext *sl);
 int ff_set_ref_count(H264Context *h, H264SliceContext *sl);
 
-int ff_h264_decode_slice_header(H264Context *h, H264SliceContext *sl, H264Context *h0);
+int ff_h264_decode_slice_header(H264Context *h, H264SliceContext *sl);
 int ff_h264_execute_decode_slices(H264Context *h, unsigned context_count);
 int ff_h264_update_thread_context(AVCodecContext *dst,
                                   const AVCodecContext *src);