[vlc-commits] demux: mkv: process block additions for WEBVTT

[Francois Cartegnie]

vlc/vlc-3.0 | branch: master | Francois Cartegnie <fcvlcdev at free.fr> | Thu Jul 16 09:54:07 2020 +0200| [f176de7447c1198a0b7c2c19d57a940fccaf750c] | committer: Francois Cartegnie

demux: mkv: process block additions for WEBVTT

(cherry picked from commit 967bf75afc5b2bc6a648355f2bb24f664e6bc77a)

> http://git.videolan.org/gitweb.cgi/vlc/vlc-3.0.git/?a=commit;h=f176de7447c1198a0b7c2c19d57a940fccaf750c
---

 modules/demux/mkv/mkv.cpp  | 18 +++++++++++++++-
 modules/demux/mkv/util.cpp | 52 +++++++++++++++++++++++++++++++---------------
 modules/demux/mkv/util.hpp |  3 ++-
 3 files changed, 54 insertions(+), 19 deletions(-)

diff --git a/modules/demux/mkv/mkv.cpp b/modules/demux/mkv/mkv.cpp
index 647ec0ebac..9fecb52ed6 100644
--- a/modules/demux/mkv/mkv.cpp
+++ b/modules/demux/mkv/mkv.cpp
@@ -607,8 +607,24 @@ void BlockDecode( demux_t *p_demux, KaxBlock *block, KaxSimpleBlock *simpleblock
 
          case VLC_CODEC_WEBVTT:
             {
+                const uint8_t *p_addition = NULL;
+                size_t i_addition = 0;
+                if(additions)
+                {
+                    KaxBlockMore *blockmore = FindChild<KaxBlockMore>(*additions);
+                    if(blockmore)
+                    {
+                        KaxBlockAdditional *addition = FindChild<KaxBlockAdditional>(*blockmore);
+                        if(addition)
+                        {
+                            i_addition = static_cast<std::string::size_type>(addition->GetSize());
+                            p_addition = reinterpret_cast<const uint8_t *>(addition->GetBuffer());
+                        }
+                    }
+                }
                 p_block = WEBVTT_Repack_Sample( p_block, /* D_WEBVTT -> webm */
-                                         !p_track->codec.compare( 0, 1, "D" ) );
+                                                !p_track->codec.compare( 0, 1, "D" ),
+                                                p_addition, i_addition );
                 if( !p_block )
                     continue;
             }
diff --git a/modules/demux/mkv/util.cpp b/modules/demux/mkv/util.cpp
index 9104deab0c..8afed9df72 100644
--- a/modules/demux/mkv/util.cpp
+++ b/modules/demux/mkv/util.cpp
@@ -243,20 +243,38 @@ void handle_real_audio(demux_t * p_demux, mkv_track_t * p_tk, block_t * p_blk, m
     }
 }
 
-block_t *WEBVTT_Repack_Sample(block_t *p_block, bool b_webm)
+block_t *WEBVTT_Repack_Sample(block_t *p_block, bool b_webm,
+                              const uint8_t *p_add, size_t i_add)
 {
     struct webvtt_cueelements_s els;
     memset(&els, 0, sizeof(els));
+    size_t newsize = 0;
+    block_t *newblock = nullptr;
     /* Repack to ISOBMFF samples format */
     if( !b_webm ) /* S_TEXT/WEBVTT */
     {
-        p_block = block_Realloc( p_block, 16, p_block->i_buffer );
-        if( !p_block )
-            return NULL;
-        SetDWBE( p_block->p_buffer, p_block->i_buffer );
-        memcpy(  &p_block->p_buffer[ 4], "vttc", 4 );
-        SetDWBE( &p_block->p_buffer[ 8], p_block->i_buffer - 8 );
-        memcpy(  &p_block->p_buffer[12], "payl", 4 );
+        /* process addition fields */
+        if( i_add )
+        {
+            const uint8_t *end = p_add + i_add;
+            const uint8_t *iden =
+                    reinterpret_cast<const uint8_t *>(std::memchr( p_add, '\n', i_add ));
+            if( iden && ++iden != end )
+            {
+                els.sttg.p_data = p_add;
+                els.sttg.i_data = &iden[-1] - p_add;
+                const uint8_t *comm =
+                        reinterpret_cast<const uint8_t *>(std::memchr( iden, '\n', end - iden ));
+                els.iden.p_data = iden;
+                if( comm )
+                    els.iden.i_data = comm - iden;
+                else
+                    els.iden.i_data = end - iden;
+            }
+        }
+        /* the payload being in the block */
+        els.payl.p_data = p_block->p_buffer;
+        els.payl.i_data = p_block->i_buffer;
     }
     else /* deprecated D_WEBVTT/ */
     {
@@ -276,16 +294,16 @@ block_t *WEBVTT_Repack_Sample(block_t *p_block, bool b_webm)
         els.sttg.i_data = &payl[-1] - sttg;
         els.payl.p_data = payl;
         els.payl.i_data = end - payl;
-        size_t newsize = WEBVTT_Pack_CueElementsGetNewSize( &els );
-        block_t *newblock = block_Alloc( newsize );
-        if( !newblock )
-            goto error;
-        WEBVTT_Pack_CueElements( &els, newblock->p_buffer );
-        block_CopyProperties( newblock, p_block );
-        block_Release( p_block );
-        return newblock;
     }
-    return p_block;
+
+    newsize = WEBVTT_Pack_CueElementsGetNewSize( &els );
+    newblock = block_Alloc( newsize );
+    if( !newblock )
+        goto error;
+    WEBVTT_Pack_CueElements( &els, newblock->p_buffer );
+    block_CopyProperties( newblock, p_block );
+    block_Release( p_block );
+    return newblock;
 
 error:
     block_Release( p_block );
diff --git a/modules/demux/mkv/util.hpp b/modules/demux/mkv/util.hpp
index f89e1cc89f..2cb6e90082 100644
--- a/modules/demux/mkv/util.hpp
+++ b/modules/demux/mkv/util.hpp
@@ -32,7 +32,8 @@ block_t *block_zlib_decompress( vlc_object_t *p_this, block_t *p_in_block );
 
 block_t *MemToBlock( uint8_t *p_mem, size_t i_mem, size_t offset);
 void handle_real_audio(demux_t * p_demux, mkv_track_t * p_tk, block_t * p_blk, mtime_t i_pts);
-block_t *WEBVTT_Repack_Sample(block_t *p_block, bool b_webm = false);
+block_t *WEBVTT_Repack_Sample(block_t *p_block, bool b_webm = false,
+                              const uint8_t * = NULL, size_t = 0);
 void send_Block( demux_t * p_demux, mkv_track_t * p_tk, block_t * p_block, unsigned int i_number_frames, mtime_t i_duration );