[vlc-devel] [RFC/WIP PATCH 3/3] decoder: add "packetized decoder" type

[Thomas Guillem]

These type of decoders must call decoder_RequestPacketizer() at Open() to query
a specific packetizer. They shoud also release the requested packetizer in
Close() or if Open() fails.

Calling decoder_RequestPacketizer() from Open() will cause the p_dec->fmt_in to
change (updated by the packetizer).

Usecase:
 - mediacodec module can force h264 or hevc packetizer. This will allow to
   remove a lot of duplicated code.

TODO: handle decoder restart when packetizer fmt changes.
---
 include/vlc_codec.h |  6 ++++++
 src/input/decoder.c | 53 ++++++++++++++++++++++++++++++++++++++++++++++-------
 src/libvlccore.sym  |  1 +
 3 files changed, 53 insertions(+), 7 deletions(-)

diff --git a/include/vlc_codec.h b/include/vlc_codec.h
index 2d01d26..2f98c7c 100644
--- a/include/vlc_codec.h
+++ b/include/vlc_codec.h
@@ -368,6 +368,12 @@ VLC_API block_t * decoder_NewAudioBuffer( decoder_t *, int i_size ) VLC_USED;
 VLC_API subpicture_t * decoder_NewSubpicture( decoder_t *, const subpicture_updater_t * ) VLC_USED;
 
 /**
+ * @param psz_packetizer_name if not NULL, request the specific packetizer. If
+ * null, release a previously requested packetizer.
+ */
+VLC_API int decoder_RequestPacketizer( decoder_t *, const char *psz_packetizer_name );
+
+/**
  * This function gives all input attachments at once.
  *
  * You MUST release the returned values
diff --git a/src/input/decoder.c b/src/input/decoder.c
index 6987fed..90c2b61 100644
--- a/src/input/decoder.c
+++ b/src/input/decoder.c
@@ -588,6 +588,32 @@ subpicture_t *decoder_NewSubpicture( decoder_t *p_decoder,
     return p_subpicture;
 }
 
+int decoder_RequestPacketizer( decoder_t *p_dec, const char *psz_packetizer_name )
+{
+    decoder_owner_sys_t *p_owner = p_dec->p_owner;
+
+    if( psz_packetizer_name != NULL )
+    {
+        assert( p_owner->p_packetizer == NULL );
+
+        int i_ret = CreateExtraPacketizer( p_dec, &p_dec->fmt_in,
+                                           psz_packetizer_name );
+        if( i_ret != VLC_SUCCESS )
+            return i_ret;
+        es_format_Copy( &p_dec->fmt_in, &p_owner->p_packetizer->fmt_out );
+        return VLC_SUCCESS;
+    }
+    else
+    {
+        assert( p_owner->p_packetizer != NULL );
+
+        UnloadDecoder( p_owner->p_packetizer );
+        vlc_object_release( p_owner->p_packetizer );
+        p_owner->p_packetizer = NULL;
+        return VLC_SUCCESS;
+    }
+}
+
 /* decoder_GetInputAttachments:
  */
 int decoder_GetInputAttachments( decoder_t *p_dec,
@@ -1620,15 +1646,28 @@ static decoder_t * CreateDecoder( vlc_object_t *p_parent,
     p_dec->pf_queue_audio = DecoderQueueAudio;
     p_dec->pf_queue_sub = DecoderQueueSpu;
 
-    /* Load a packetizer module if the input is not already packetized */
-    if( p_sout == NULL && !fmt->b_packetized )
+    if( p_sout == NULL )
     {
-        if( CreateExtraPacketizer( p_dec, fmt, NULL ) == VLC_SUCCESS )
-            fmt = &p_owner->p_packetizer->fmt_out;
-    }
+        /* Try first to load a decoder that need a specific packetizer */
+        if( LoadDecoder( p_dec, "packetized decoder", NULL, fmt ) == 0 )
+        {
+            assert( p_owner->p_packetizer != NULL );
+        }
+        else
+        {
+            assert( p_owner->p_packetizer == NULL );
 
-    /* Find a suitable decoder/packetizer module */
-    if( LoadDecoder( p_dec, p_sout == NULL ? "decoder" : "packetizer", NULL, fmt ) )
+            /* Load a packetizer module if the input is not already packetized */
+            if( !fmt->b_packetized
+             && CreateExtraPacketizer( p_dec, fmt, NULL ) == VLC_SUCCESS )
+                fmt = &p_owner->p_packetizer->fmt_out;
+
+            /* Load a decoder */
+            if( LoadDecoder( p_dec, "decoder", NULL, fmt ) )
+                return p_dec;
+        }
+    }
+    else if( LoadDecoder( p_dec, "packetizer", NULL, fmt ) )
         return p_dec;
 
     /* Copy ourself the input replay gain */
diff --git a/src/libvlccore.sym b/src/libvlccore.sym
index 89e74f8..310ecd4 100644
--- a/src/libvlccore.sym
+++ b/src/libvlccore.sym
@@ -82,6 +82,7 @@ decoder_GetDisplayRate
 decoder_GetInputAttachments
 decoder_NewAudioBuffer
 decoder_NewSubpicture
+decoder_RequestPacketizer
 decoder_SynchroChoose
 decoder_SynchroDate
 decoder_SynchroDecode
-- 
2.8.1