[vlc-commits] dav1d: parse the extra data to get the output chroma

[Steve Lhomme]

vlc | branch: master | Steve Lhomme <robux4 at ycbcr.xyz> | Wed Sep  9 15:59:54 2020 +0200| [3c64e71e36a5ee83708eee40060dabfcbe7044f4] | committer: Steve Lhomme

dav1d: parse the extra data to get the output chroma

If there are some extra data, the chroma should be constant and we can estimate
it so that we create the decoder output with the proper chroma on open.

> http://git.videolan.org/gitweb.cgi/vlc.git/?a=commit;h=3c64e71e36a5ee83708eee40060dabfcbe7044f4
---

 modules/codec/Makefile.am |  3 ++-
 modules/codec/dav1d.c     | 53 ++++++++++++++++++++++++++++++++++++++++++-----
 2 files changed, 50 insertions(+), 6 deletions(-)

diff --git a/modules/codec/Makefile.am b/modules/codec/Makefile.am
index ec6447ddf9..6995119e07 100644
--- a/modules/codec/Makefile.am
+++ b/modules/codec/Makefile.am
@@ -560,7 +560,8 @@ libtwolame_plugin_la_LIBADD = $(TWOLAME_LIBS) $(LIBM)
 EXTRA_LTLIBRARIES += libtwolame_plugin.la
 codec_LTLIBRARIES += $(LTLIBtwolame)
 
-libdav1d_plugin_la_SOURCES = codec/dav1d.c
+libdav1d_plugin_la_SOURCES = codec/dav1d.c \
+	packetizer/av1_obu.c packetizer/av1_obu.h
 libdav1d_plugin_la_CPPFLAGS = $(AM_CPPFLAGS) $(DAV1D_CFLAGS)
 libdav1d_plugin_la_CFLAGS = $(AM_CFLAGS)
 libdav1d_plugin_la_LDFLAGS = $(AM_LDFLAGS) -rpath '$(codecdir)'
diff --git a/modules/codec/dav1d.c b/modules/codec/dav1d.c
index 92f6f44146..23b4eb9cda 100644
--- a/modules/codec/dav1d.c
+++ b/modules/codec/dav1d.c
@@ -38,6 +38,7 @@
 #include <dav1d/dav1d.h>
 
 #include "../packetizer/iso_color_tables.h"
+#include "../packetizer/av1_obu.h"
 #include "cc.h"
 
 /****************************************************************************
@@ -391,6 +392,37 @@ static int OpenDecoder(vlc_object_t *p_this)
     p_sys->s.allocator.alloc_picture_callback = NewPicture;
     p_sys->s.allocator.release_picture_callback = FreePicture;
 
+    av1_OBU_sequence_header_t *sequence_hdr = NULL;
+    if (dec->fmt_in.i_extra > 4)
+    {
+        // in ISOBMFF/WebM/Matroska the first 4 bytes are from the AV1CodecConfigurationBox
+        // and then one or more OBU
+        const uint8_t *obu_start = ((const uint8_t*) dec->fmt_in.p_extra) + 4;
+        int obu_size = dec->fmt_in.i_extra - 4;
+        if (AV1_OBUIsValid(obu_start, obu_size) && AV1_OBUGetType(obu_start) == AV1_OBU_SEQUENCE_HEADER)
+            sequence_hdr = AV1_OBU_parse_sequence_header(obu_start, obu_size);
+    }
+
+    if (!sequence_hdr)
+    {
+        dec->fmt_out.i_codec = VLC_CODEC_I420;
+        dec->fmt_out.video.i_width = dec->fmt_in.video.i_width;
+        dec->fmt_out.video.i_height = dec->fmt_in.video.i_height;
+    }
+    else
+    {
+        // use the sequence header to get a better chroma to start with
+        dec->fmt_out.i_codec = AV1_get_chroma(sequence_hdr);
+
+        AV1_get_frame_max_dimensions(sequence_hdr, &dec->fmt_out.video.i_width, &dec->fmt_out.video.i_height);
+
+        if (dec->fmt_out.video.transfer == TRANSFER_FUNC_UNDEF)
+            AV1_get_colorimetry(sequence_hdr, &dec->fmt_out.video.primaries, &dec->fmt_out.video.transfer,
+                                &dec->fmt_out.video.space, &dec->fmt_out.video.color_range);
+    }
+    dec->fmt_out.video.i_visible_width  = dec->fmt_out.video.i_width;
+    dec->fmt_out.video.i_visible_height = dec->fmt_out.video.i_height;
+
     if (dav1d_open(&p_sys->c, &p_sys->s) < 0)
     {
         msg_Err(p_this, "Could not open the Dav1d decoder");
@@ -400,13 +432,10 @@ static int OpenDecoder(vlc_object_t *p_this)
     msg_Dbg(p_this, "Using dav1d version %s with %d/%d frame/tile threads",
             dav1d_version(), p_sys->s.n_frame_threads, p_sys->s.n_tile_threads);
 
-    dec->pf_decode = Decode;
-    dec->pf_flush = FlushDecoder;
     dec->i_extra_picture_buffers = (p_sys->s.n_frame_threads - 1);
+    dec->fmt_out.video.i_width  = (dec->fmt_out.video.i_width + 0x7F) & ~0x7F;
+    dec->fmt_out.video.i_height = (dec->fmt_out.video.i_height + 0x7F) & ~0x7F;
 
-    dec->fmt_out.video.i_width = dec->fmt_in.video.i_width;
-    dec->fmt_out.video.i_height = dec->fmt_in.video.i_height;
-    dec->fmt_out.i_codec = VLC_CODEC_I420;
     dec->p_sys = p_sys;
 
     if (dec->fmt_in.video.i_sar_num > 0 && dec->fmt_in.video.i_sar_den > 0) {
@@ -420,6 +449,20 @@ static int OpenDecoder(vlc_object_t *p_this)
     dec->fmt_out.video.mastering   = dec->fmt_in.video.mastering;
     dec->fmt_out.video.lighting    = dec->fmt_in.video.lighting;
 
+    if (sequence_hdr != NULL)
+    {
+        // we have the proper chroma, make sure we can use it
+        AV1_release_sequence_header(sequence_hdr);
+
+        if (decoder_UpdateVideoFormat(dec) != 0)
+        {
+            CloseDecoder(VLC_OBJECT(dec));
+            return VLC_EGENERIC;
+        }
+    }
+    dec->pf_decode = Decode;
+    dec->pf_flush = FlushDecoder;
+
     cc_Init(&p_sys->cc);
 
     return VLC_SUCCESS;