libhb: pass AV_PKT_FLAG_DISCARD through to decoder

Edit list cuts are not always on keyframe boundaries and therefore
sometimes require dropping frames after decoding them.
AV_PKT_FLAG_DISCARD tells us when to do this.

Fixes https://github.com/HandBrake/HandBrake/issues/1900

3 files changed, 13 insertions, 1 deletions

diff --git a/libhb/decavcodec.c b/libhb/decavcodec.c
index 6fcdefa9d..610f9ecfa 100644
--- a/libhb/decavcodec.c
+++ b/libhb/decavcodec.c
@@ -82,6 +82,7 @@ typedef struct
     int                    frametype;
     int                    scr_sequence;
     int                    new_chap;
+    int                    discard;
 } packet_info_t;
 
 typedef struct reordered_data_s reordered_data_t;
@@ -489,6 +490,7 @@ static int decavcodecaWork( hb_work_object_t * w, hb_buffer_t ** buf_in,
         pv->packet_info.scr_sequence = in->s.scr_sequence;
         pv->packet_info.new_chap     = in->s.new_chap;
         pv->packet_info.frametype    = in->s.frametype;
+        pv->packet_info.discard      = !!(in->s.flags & HB_FLAG_DISCARD);
     }
     for (pos = 0; pos < in->size; pos += len)
     {
@@ -522,6 +524,7 @@ static int decavcodecaWork( hb_work_object_t * w, hb_buffer_t ** buf_in,
             // decodeAudio that is now finished.  The next packet is associated
             // with the input buffer, so set it's chapter and scr info.
             pv->packet_info.scr_sequence = in->s.scr_sequence;
+            pv->packet_info.discard      = !!(in->s.flags & HB_FLAG_DISCARD);
             pv->unfinished               = 0;
         }
         if (len > 0 && pout_len <= 0)
@@ -1319,6 +1322,7 @@ static int decodeFrame( hb_work_private_t * pv, packet_info_t * packet_info )
         {
             avp.flags |= AV_PKT_FLAG_KEY;
         }
+        avp.flags  |= packet_info->discard * AV_PKT_FLAG_DISCARD;
     }
     else
     {
@@ -1748,6 +1752,7 @@ static int decavcodecvWork( hb_work_object_t * w, hb_buffer_t ** buf_in,
         pv->packet_info.scr_sequence = in->s.scr_sequence;
         pv->packet_info.new_chap     = in->s.new_chap;
         pv->packet_info.frametype    = in->s.frametype;
+        pv->packet_info.discard      = !!(in->s.flags & HB_FLAG_DISCARD);
     }
     for (pos = 0; pos < in->size; pos += len)
     {
@@ -1802,6 +1807,7 @@ static int decavcodecvWork( hb_work_object_t * w, hb_buffer_t ** buf_in,
             pv->packet_info.scr_sequence = in->s.scr_sequence;
             pv->packet_info.new_chap     = in->s.new_chap;
             pv->packet_info.frametype    = in->s.frametype;
+            pv->packet_info.discard      = !!(in->s.flags & HB_FLAG_DISCARD);
             pv->unfinished               = 0;
         }
         if (len > 0 && pout_len <= 0)
@@ -2168,6 +2174,7 @@ static void decodeAudio(hb_work_private_t *pv, packet_info_t * packet_info)
         avp.size = packet_info->size;
         avp.pts  = packet_info->pts;
         avp.dts  = AV_NOPTS_VALUE;
+        avp.flags |= packet_info->discard * AV_PKT_FLAG_DISCARD;
     }
     else
     {
diff --git a/libhb/internal.h b/libhb/internal.h
index 1e9138a3f..49e081169 100644
--- a/libhb/internal.h
+++ b/libhb/internal.h
@@ -102,6 +102,7 @@ struct hb_buffer_settings_s
 #define HB_BUF_FLAG_EOS             0x0800
 #define HB_FLAG_FRAMETYPE_KEY       0x1000
 #define HB_FLAG_FRAMETYPE_REF       0x2000
+#define HB_FLAG_DISCARD             0x4000
     uint16_t      flags;
 
 #define HB_COMB_NONE  0
diff --git a/libhb/stream.c b/libhb/stream.c
index 0c86f2a8b..ca8739190 100644
--- a/libhb/stream.c
+++ b/libhb/stream.c
@@ -5946,6 +5946,10 @@ hb_buffer_t * hb_ffmpeg_read( hb_stream_t *stream )
             memcpy( buf->palette->data, palette, size );
         }
     }
+    if (stream->ffmpeg_pkt.flags & AV_PKT_FLAG_DISCARD)
+    {
+        buf->s.flags |= HB_FLAG_DISCARD;
+    }
     buf->s.id = stream->ffmpeg_pkt.stream_index;
 
     // compute a conversion factor to go from the ffmpeg
@@ -5975,7 +5979,7 @@ hb_buffer_t * hb_ffmpeg_read( hb_stream_t *stream )
              */
             if (stream->ffmpeg_pkt.flags & AV_PKT_FLAG_KEY)
             {
-                buf->s.flags = HB_FLAG_FRAMETYPE_KEY;
+                buf->s.flags |= HB_FLAG_FRAMETYPE_KEY;
                 buf->s.frametype = HB_FRAME_I;
             }
             break;