[vlc-devel] [PATCH v3] Add support for GoPro HiLight tags as chapters

[Emeric Grange]

---
 modules/demux/mp4/libmp4.c | 30 ++++++++++++++++++++++++++++++
 modules/demux/mp4/libmp4.h |  9 +++++++++
 modules/demux/mp4/mp4.c    | 25 +++++++++++++++++++++++++
 3 files changed, 64 insertions(+)

diff --git a/modules/demux/mp4/libmp4.c b/modules/demux/mp4/libmp4.c
index d049fa4..a0817dc 100644
--- a/modules/demux/mp4/libmp4.c
+++ b/modules/demux/mp4/libmp4.c
@@ -3378,6 +3378,35 @@ static int MP4_ReadBox_chpl( stream_t *p_stream, MP4_Box_t *p_box )
     MP4_READBOX_EXIT( 1 );
 }

+/* GoPro HiLight tags support */
+static int MP4_ReadBox_HMMT( stream_t *p_stream, MP4_Box_t *p_box )
+{
+    MP4_Box_data_HMMT_t *p_hmmt;
+    MP4_READBOX_ENTER( MP4_Box_data_HMMT_t, NULL );
+
+    if ( i_read < 5 )
+        MP4_READBOX_EXIT( 0 );
+
+    p_hmmt = p_box->data.p_hmmt;
+
+    MP4_GET4BYTES( p_hmmt->i_chapter_count );
+
+    if ( i_read < p_hmmt->i_chapter_count*4 )
+        MP4_READBOX_EXIT( 0 );
+
+    if ( p_hmmt->i_chapter_count > 100 )
+        p_hmmt->i_chapter_count = 100;
+
+    for( uint32_t i = 0; i < p_hmmt->i_chapter_count; i++ )
+    {
+        MP4_GET4BYTES( p_hmmt->i_chapter_start[i] );
+    }
+
+    msg_Dbg( p_stream, "read box: \"HMMT\" %d HiLight tags", p_hmmt->i_chapter_count );
+
+    MP4_READBOX_EXIT( 1 );
+}
+
 static void MP4_FreeBox_tref_generic( MP4_Box_t *p_box )
 {
     FREENULL( p_box->data.p_tref_generic->i_track_ID );
@@ -4224,6 +4253,7 @@ static const struct
     { ATOM_name,    MP4_ReadBox_String,    ATOM_udta },
     { ATOM_vndr,    MP4_ReadBox_String,    ATOM_udta },
     { ATOM_SDLN,    MP4_ReadBox_String,    ATOM_udta },
+    { ATOM_HMMT,    MP4_ReadBox_HMMT,      ATOM_udta }, /* GoPro HiLights */

     /* udta, non meta */
     { ATOM_tsel,    MP4_ReadBox_tsel,    ATOM_udta },
diff --git a/modules/demux/mp4/libmp4.h b/modules/demux/mp4/libmp4.h
index 3e66350..aba0d14 100644
--- a/modules/demux/mp4/libmp4.h
+++ b/modules/demux/mp4/libmp4.h
@@ -331,6 +331,7 @@ typedef int64_t stime_t;
 #define ATOM_0xa9xyz VLC_FOURCC( 0xa9, 'x', 'y', 'z' )
 #define ATOM_aART VLC_FOURCC( 'a', 'A', 'R', 'T' )
 #define ATOM_chpl VLC_FOURCC( 'c', 'h', 'p', 'l' )
+#define ATOM_HMMT VLC_FOURCC( 'H', 'M', 'M', 'T' )
 #define ATOM_disk VLC_FOURCC( 'd', 'i', 's', 'k' )
 #define ATOM_WLOC VLC_FOURCC( 'W', 'L', 'O', 'C' )

@@ -1202,6 +1203,13 @@ typedef struct

 typedef struct
 {
+    uint32_t i_chapter_count;
+    uint32_t i_chapter_start[100];
+
+} MP4_Box_data_HMMT_t;
+
+typedef struct
+{
     uint8_t i_version;
     uint8_t i_profile;
     uint8_t i_profile_compatibility;
@@ -1608,6 +1616,7 @@ typedef union MP4_Box_data_s

     MP4_Box_data_pnot_t *p_pnot;
     MP4_Box_data_chpl_t *p_chpl;
+    MP4_Box_data_HMMT_t *p_hmmt;
     MP4_Box_data_tref_generic_t *p_tref_generic;

     MP4_Box_data_tfrf_t *p_tfrf;
diff --git a/modules/demux/mp4/mp4.c b/modules/demux/mp4/mp4.c
index a7d11f1..578671e 100644
--- a/modules/demux/mp4/mp4.c
+++ b/modules/demux/mp4/mp4.c
@@ -1811,6 +1811,25 @@ static void LoadChapterGpac( demux_t  *p_demux, MP4_Box_t *p_chpl )
         TAB_APPEND( p_sys->p_title->i_seekpoint, p_sys->p_title->seekpoint, s );
     }
 }
+static void LoadChapterGoPro( demux_t *p_demux, MP4_Box_t *p_hmmt )
+{
+    demux_sys_t *p_sys = p_demux->p_sys;
+
+    p_sys->p_title = vlc_input_title_New();
+    for( unsigned i = 0; i < BOXDATA(p_hmmt)->i_chapter_count; i++ )
+    {
+        seekpoint_t *s = vlc_seekpoint_New();
+        if (s)
+        {
+            asprintf( &s->psz_name, "HiLight tag #%u", i+1 );
+            EnsureUTF8( s->psz_name );
+
+            // HiLights are expressed in ms, need convertion to µs
+            s->i_time_offset = BOXDATA(p_hmmt)->i_chapter_start[i] * 1000;
+            TAB_APPEND( p_sys->p_title->i_seekpoint, p_sys->p_title->seekpoint, s );
+        }
+    }
+}
 static void LoadChapterApple( demux_t  *p_demux, mp4_track_t *tk )
 {
     demux_sys_t *p_sys = p_demux->p_sys;
@@ -1854,12 +1873,18 @@ static void LoadChapter( demux_t  *p_demux )
 {
     demux_sys_t *p_sys = p_demux->p_sys;
     MP4_Box_t *p_chpl;
+    MP4_Box_t *p_hmmt;

     if( ( p_chpl = MP4_BoxGet( p_sys->p_root, "/moov/udta/chpl" ) ) &&
           BOXDATA(p_chpl) && BOXDATA(p_chpl)->i_chapter > 0 )
     {
         LoadChapterGpac( p_demux, p_chpl );
     }
+    else if( ( p_hmmt = MP4_BoxGet( p_sys->p_root, "/moov/udta/HMMT" ) ) &&
+             BOXDATA(p_hmmt) && BOXDATA(p_hmmt)->i_chapter_count > 0 )
+    {
+        LoadChapterGoPro( p_demux, p_hmmt );
+    }
     else if( p_sys->p_tref_chap )
     {
         MP4_Box_data_tref_generic_t *p_chap = p_sys->p_tref_chap->data.p_tref_generic;
--
2.8.3