avcodec/h264: Partially decode and display single fields try #2

This like the previous attempt does not fully correctly decode this
type of non standard H.264, but it now works fully automatic
requiring no manual filters or flags to be used

See Ticket2254

Reviewed-by: Kieran Kunhya <kierank@obe.tv>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

1 files changed, 27 insertions, 1 deletions

diff --git a/libavcodec/h264.c b/libavcodec/h264.c
index ab9acde7cb..23f775414f 100644
--- a/libavcodec/h264.c
+++ b/libavcodec/h264.c
@@ -762,7 +762,10 @@ static void decode_postinit(H264Context *h, int setup_finished)
          * yet, so we assume the worst for now. */
         // if (setup_finished)
         //    ff_thread_finish_setup(h->avctx);
-        return;
+        if (cur->field_poc[0] == INT_MAX && cur->field_poc[1] == INT_MAX)
+            return;
+        if (h->avctx->hwaccel || h->missing_fields <=1)
+            return;
     }
 
     cur->f.interlaced_frame = 0;
@@ -1912,6 +1915,29 @@ static int h264_decode_frame(AVCodecContext *avctx, void *data,
             if (!h->next_output_pic->recovered)
                 h->next_output_pic->f.flags |= AV_FRAME_FLAG_CORRUPT;
 
+            if (!h->avctx->hwaccel &&
+                 (h->next_output_pic->field_poc[0] == INT_MAX ||
+                  h->next_output_pic->field_poc[1] == INT_MAX)
+            ) {
+                int p;
+                AVFrame *f = &h->next_output_pic->f;
+                int field = h->next_output_pic->field_poc[0] == INT_MAX;
+                uint8_t *dst_data[4];
+                int linesizes[4];
+                const uint8_t *src_data[4];
+
+                av_log(h->avctx, AV_LOG_DEBUG, "Duplicating field %d to fill missing\n", field);
+
+                for (p = 0; p<4; p++) {
+                    dst_data[p] = f->data[p] + (field^1)*f->linesize[p];
+                    src_data[p] = f->data[p] +  field   *f->linesize[p];
+                    linesizes[p] = 2*f->linesize[p];
+                }
+
+                av_image_copy(dst_data, linesizes, src_data, linesizes,
+                              f->format, f->width, f->height>>1);
+            }
+
             ret = output_frame(h, pict, h->next_output_pic);
             if (ret < 0)
                 return ret;