Merge commit '99c554ef'

* commit '99c554ef':
  h264: eliminate low_delay

ff_print_debug_info2() is adjusted to allow a NULL pointer as low_delay.
It's only useful for MPEG codecs with the exception of H264.
Merged-by: Clément Bœsch <clement@stupeflix.com>

libavcodec/h264.c

@@ -368,10 +368,6 @@ av_cold int ff_h264_decode_init(AVCodecContext *avctx)
     if (ret < 0)
         return ret;
 
-    /* set defaults */
-    if (!avctx->has_b_frames)
-        h->low_delay = 1;
-
     ret = ff_thread_once(&h264_vlc_init, ff_h264_decode_init_vlc);
     if (ret != 0) {
         av_log(avctx, AV_LOG_ERROR, "pthread_once has failed.");
@@ -401,7 +397,6 @@ av_cold int ff_h264_decode_init(AVCodecContext *avctx)
     if (h->ps.sps && h->ps.sps->bitstream_restriction_flag &&
         h->avctx->has_b_frames < h->ps.sps->num_reorder_frames) {
         h->avctx->has_b_frames = h->ps.sps->num_reorder_frames;
-        h->low_delay           = 0;
     }
 
     avctx->internal->allocate_progress = 1;
@@ -631,7 +626,6 @@ static void decode_postinit(H264Context *h, int setup_finished)
         h->avctx->strict_std_compliance >= FF_COMPLIANCE_STRICT) {
         h->avctx->has_b_frames = FFMAX(h->avctx->has_b_frames, sps->num_reorder_frames);
     }
-    h->low_delay = !h->avctx->has_b_frames;
 
     for (i = 0; 1; i++) {
         if(i == MAX_DELAYED_PIC_COUNT || cur->poc < h->last_pocs[i]){
@@ -655,7 +649,6 @@ static void decode_postinit(H264Context *h, int setup_finished)
     } else if(h->avctx->has_b_frames < out_of_order && !sps->bitstream_restriction_flag){
         av_log(h->avctx, AV_LOG_INFO, "Increasing reorder buffer to %d\n", out_of_order);
         h->avctx->has_b_frames = out_of_order;
-        h->low_delay = 0;
     }
 
     pics = 0;
@@ -1353,7 +1346,7 @@ static int h264_decode_frame(AVCodecContext *avctx, void *data,
                                     h->next_output_pic->mb_type,
                                     h->next_output_pic->qscale_table,
                                     h->next_output_pic->motion_val,
-                                    &h->low_delay,
+                                    NULL,
                                     h->mb_width, h->mb_height, h->mb_stride, 1);
             }
         }

libavcodec/h264.h

@@ -494,7 +494,6 @@ typedef struct H264Context {
 
     int droppable;
     int coded_picture_number;
-    int low_delay;
 
     int context_initialized;
     int flags;

libavcodec/h264_slice.c

@@ -386,7 +386,6 @@ int ff_h264_update_thread_context(AVCodecContext *dst,
     h->first_field          = h1->first_field;
     h->picture_structure    = h1->picture_structure;
     h->droppable            = h1->droppable;
-    h->low_delay            = h1->low_delay;
     h->backup_width         = h1->backup_width;
     h->backup_height        = h1->backup_height;
     h->backup_pix_fmt       = h1->backup_pix_fmt;
@@ -408,7 +407,6 @@ int ff_h264_update_thread_context(AVCodecContext *dst,
 
     h->enable_er       = h1->enable_er;
     h->workaround_bugs = h1->workaround_bugs;
-    h->low_delay       = h1->low_delay;
     h->droppable       = h1->droppable;
 
     // extradata/NAL handling
@@ -1218,20 +1216,6 @@ int ff_h264_decode_slice_header(H264Context *h, H264SliceContext *sl)
         if (h->bit_depth_luma    != h->ps.sps->bit_depth_luma ||
             h->chroma_format_idc != h->ps.sps->chroma_format_idc)
             needs_reinit         = 1;
-
-        if (h->flags & AV_CODEC_FLAG_LOW_DELAY ||
-            (h->ps.sps->bitstream_restriction_flag &&
-             !h->ps.sps->num_reorder_frames)) {
-            if (h->avctx->has_b_frames > 1 || h->delayed_pic[0])
-                av_log(h->avctx, AV_LOG_WARNING, "Delayed frames seen. "
-                       "Reenabling low delay requires a codec flush.\n");
-            else
-                h->low_delay = 1;
-        }
-
-        if (h->avctx->has_b_frames < 2)
-            h->avctx->has_b_frames = !h->low_delay;
-
     }
 
     pps = h->ps.pps;

libavcodec/mpegvideo.c

@@ -1757,7 +1757,8 @@ void ff_print_debug_info2(AVCodecContext *avctx, AVFrame *pict, uint8_t *mbskip_
         const int mv_stride      = (mb_width << mv_sample_log2) +
                                    (avctx->codec->id == AV_CODEC_ID_H264 ? 0 : 1);
 
-        *low_delay = 0; // needed to see the vectors without trashing the buffers
+        if (low_delay)
+            *low_delay = 0; // needed to see the vectors without trashing the buffers
 
         avcodec_get_chroma_sub_sample(avctx->pix_fmt, &h_chroma_shift, &v_chroma_shift);