[vlc-commits] packetizer: h264: gather nals incrementally

[Francois Cartegnie]

vlc | branch: master | Francois Cartegnie <fcvlcdev at free.fr> | Wed Mar 15 17:15:34 2017 +0100| [55428248fb06924d0b0fe522870e5628f1dd31d5] | committer: Francois Cartegnie

packetizer: h264: gather nals incrementally

allows to insert something else than sps/pps
and uses last block pointer

> http://git.videolan.org/gitweb.cgi/vlc.git/?a=commit;h=55428248fb06924d0b0fe522870e5628f1dd31d5
---

 modules/packetizer/h264.c | 61 +++++++++++++++++++++++++++--------------------
 1 file changed, 35 insertions(+), 26 deletions(-)

diff --git a/modules/packetizer/h264.c b/modules/packetizer/h264.c
index ee273e30..ae005e9 100644
--- a/modules/packetizer/h264.c
+++ b/modules/packetizer/h264.c
@@ -676,7 +676,8 @@ static block_t *ParseNALBlock( decoder_t *p_dec, bool *pb_ts_used, block_t *p_fr
 static block_t *OutputPicture( decoder_t *p_dec )
 {
     decoder_sys_t *p_sys = p_dec->p_sys;
-    block_t *p_pic;
+    block_t *p_pic = NULL;
+    block_t **pp_pic_last = &p_pic;
 
     if ( !p_sys->b_header && p_sys->i_recovery_frames != -1 )
     {
@@ -688,6 +689,12 @@ static block_t *OutputPicture( decoder_t *p_dec )
         --p_sys->i_recovery_frames;
     }
 
+    if( unlikely(!p_sys->p_frame) )
+    {
+        assert( p_sys->p_frame );
+        return NULL;
+    }
+
     if( !p_sys->b_header && p_sys->i_recovery_frames == -1 &&
          p_sys->slice.i_frame_type != BLOCK_FLAG_TYPE_I)
         return NULL;
@@ -698,49 +705,51 @@ static block_t *OutputPicture( decoder_t *p_dec )
     if( !p_pps || !p_sps )
         return NULL;
 
+    /* Gather PPS/SPS if required */
+    block_t *p_xpsnal = NULL;
+    block_t **pp_xpsnal_tail = &p_xpsnal;
     const bool b_sps_pps_i = p_sys->slice.i_frame_type == BLOCK_FLAG_TYPE_I &&
                              p_sys->p_active_pps &&
                              p_sys->p_active_sps;
     if( b_sps_pps_i || p_sys->b_new_sps || p_sys->b_new_pps )
     {
-        block_t *p_head = NULL;
-        if( p_sys->p_frame->i_flags & BLOCK_FLAG_PRIVATE_AUD )
-        {
-            p_head = p_sys->p_frame;
-            p_sys->p_frame = p_sys->p_frame->p_next;
-            if( p_sys->p_frame == NULL )
-                p_sys->pp_frame_last = &p_sys->p_frame;
-            p_head->p_next = NULL;
-        }
-
-        block_t *p_list = NULL;
-        block_t **pp_list_tail = &p_list;
         for( int i = 0; i <= H264_SPS_ID_MAX && (b_sps_pps_i || p_sys->b_new_sps); i++ )
         {
             if( p_sys->sps[i].p_block )
-                block_ChainLastAppend( &pp_list_tail, block_Duplicate( p_sys->sps[i].p_block ) );
+                block_ChainLastAppend( &pp_xpsnal_tail, block_Duplicate( p_sys->sps[i].p_block ) );
         }
         for( int i = 0; i < H264_PPS_ID_MAX && (b_sps_pps_i || p_sys->b_new_pps); i++ )
         {
             if( p_sys->pps[i].p_block )
-                block_ChainLastAppend( &pp_list_tail, block_Duplicate( p_sys->pps[i].p_block ) );
+                block_ChainLastAppend( &pp_xpsnal_tail, block_Duplicate( p_sys->pps[i].p_block ) );
         }
-        if( b_sps_pps_i && p_list )
+        if( b_sps_pps_i && p_xpsnal )
             p_sys->b_header = true;
-
-        if( p_list )
-            block_ChainAppend( &p_head, p_list );
-
-        if( p_sys->p_frame )
-            block_ChainAppend( &p_head, p_sys->p_frame );
-
-        p_pic = block_ChainGather( p_head );
     }
-    else
+
+    /* Now rebuild NAL Sequence, inserting PPS/SPS if any */
+    if( p_sys->p_frame->i_flags & BLOCK_FLAG_PRIVATE_AUD )
     {
-        p_pic = block_ChainGather( p_sys->p_frame );
+        block_t *p_au = p_sys->p_frame;
+        p_sys->p_frame = p_au->p_next;
+        p_au->p_next = NULL;
+        p_au->i_flags &= ~BLOCK_FLAG_PRIVATE_AUD;
+        block_ChainLastAppend( &pp_pic_last, p_au );
     }
 
+    if( p_xpsnal )
+        block_ChainLastAppend( &pp_pic_last, p_xpsnal );
+
+    assert( p_sys->p_frame );
+    if( p_sys->p_frame )
+        block_ChainLastAppend( &pp_pic_last, p_sys->p_frame );
+
+    /* Reset chains, now empty */
+    p_sys->p_frame = NULL;
+    p_sys->pp_frame_last = &p_sys->p_frame;
+
+    p_pic = block_ChainGather( p_pic );
+
     if( !p_pic )
         return NULL;