mpeg2: fix PAR calculation from commit 132922d.

Invoke gst_mpeg_video_finalise_mpeg2_sequence_header() to get the
correct PAR values. While doing so, require a newer version of the
bitstream parser library.

Note: it may be necessary to also parse the Sequence_Display_Extension()
header.

Signed-off-by: Sreerenj Balachandran <sreerenj.balachandran@intel.com>
Signed-off-by: Gwenole Beauchesne <gwenole.beauchesne@intel.com>

3 files changed, 38 insertions, 5 deletions

diff --git a/configure.ac b/configure.ac
index ae2ebecc..d714ac42 100644
--- a/configure.ac
+++ b/configure.ac
@@ -214,6 +214,30 @@ dnl ... bitstream parsers
 PKG_CHECK_MODULES([GST_CODEC_PARSERS],
     [gstreamer-codecparsers-$GST_MAJORMINOR >= gst_plugins_bad_version])
 
+dnl ... MPEG-2 parser, with the required extensions
+AC_CACHE_CHECK([for MPEG-2 parser],
+    ac_cv_have_gst_mpeg2_parser, [
+    saved_CPPFLAGS="$CPPFLAGS"
+    CPPFLAGS="$CPPFLAGS $GST_CFLAGS $GST_CODEC_PARSERS_CFLAGS"
+    saved_LIBS="$LIBS"
+    LIBS="$LIBS $GST_LIBS $GST_CODEC_PARSERS_LIBS"
+    AC_COMPILE_IFELSE(
+        [AC_LANG_PROGRAM(
+            [[#include <gst/codecparsers/gstmpegvideoparser.h>]],
+            [[GstMpegVideoSequenceHdr seq_hdr;
+              GstMpegVideoSequenceExt seq_ext;
+              GstMpegVideoSequenceDisplayExt seq_dpy;
+              gst_mpeg_video_finalise_mpeg2_sequence_header(&seq_hdr,
+                  &seq_ext, &seq_dpy);]])],
+        [ac_cv_have_gst_mpeg2_parser="yes"],
+        [ac_cv_have_gst_mpeg2_parser="no"]
+    )
+    CPPFLAGS="$saved_CPPFLAGS"
+    LIBS="$saved_LIBS"
+])
+AM_CONDITIONAL([USE_LOCAL_CODEC_PARSERS_MPEG2],
+    [test "$ac_cv_have_gst_mpeg2_parser" != "yes"])
+
 dnl ... H.264 parser, with the required extensions
 AC_CACHE_CHECK([for H.264 parser],
     ac_cv_have_gst_h264_parser, [
diff --git a/gst-libs/gst/codecparsers/Makefile.am b/gst-libs/gst/codecparsers/Makefile.am
index 8dd23ef9..9b40eb6a 100644
--- a/gst-libs/gst/codecparsers/Makefile.am
+++ b/gst-libs/gst/codecparsers/Makefile.am
@@ -29,6 +29,11 @@ gen_source_c += gstjpegparser.c
 gen_source_h += gstjpegparser.h
 endif
 
+if USE_LOCAL_CODEC_PARSERS_MPEG2
+gen_source_c += gstmpegvideoparser.c
+gen_source_h += gstmpegvideoparser.h
+endif
+
 if USE_LOCAL_CODEC_PARSERS_H264
 gen_source_c += gsth264parser.c
 gen_source_h += gsth264parser.h
diff --git a/gst-libs/gst/vaapi/gstvaapidecoder_mpeg2.c b/gst-libs/gst/vaapi/gstvaapidecoder_mpeg2.c
index 7b479057..8bdb13f1 100644
--- a/gst-libs/gst/vaapi/gstvaapidecoder_mpeg2.c
+++ b/gst-libs/gst/vaapi/gstvaapidecoder_mpeg2.c
@@ -519,11 +519,9 @@ decode_sequence(GstVaapiDecoderMpeg2 *decoder, guchar *buf, guint buf_size)
     pts_set_framerate(&priv->tsg, priv->fps_n, priv->fps_d);
     gst_vaapi_decoder_set_framerate(base_decoder, priv->fps_n, priv->fps_d);
 
-    gst_vaapi_decoder_set_pixel_aspect_ratio(
-        base_decoder,
-        seq_hdr->par_w,
-        seq_hdr->par_h
-    );
+    if (gst_mpeg_video_finalise_mpeg2_sequence_header(seq_hdr, NULL, NULL))
+        gst_vaapi_decoder_set_pixel_aspect_ratio(base_decoder,
+            seq_hdr->par_w, seq_hdr->par_h);
 
     priv->width                 = seq_hdr->width;
     priv->height                = seq_hdr->height;
@@ -539,6 +537,7 @@ decode_sequence_ext(GstVaapiDecoderMpeg2 *decoder, guchar *buf, guint buf_size)
 {
     GstVaapiDecoder * const base_decoder = GST_VAAPI_DECODER(decoder);
     GstVaapiDecoderMpeg2Private * const priv = decoder->priv;
+    GstMpegVideoSequenceHdr * const seq_hdr = &priv->seq_hdr;
     GstMpegVideoSequenceExt * const seq_ext = &priv->seq_ext;
     GstVaapiProfile profile;
     guint width, height;
@@ -590,6 +589,11 @@ decode_sequence_ext(GstVaapiDecoderMpeg2 *decoder, guchar *buf, guint buf_size)
         priv->profile = profile;
         priv->profile_changed = TRUE;
     }
+
+    if (gst_mpeg_video_finalise_mpeg2_sequence_header(seq_hdr, seq_ext, NULL))
+        gst_vaapi_decoder_set_pixel_aspect_ratio(base_decoder,
+            seq_hdr->par_w, seq_hdr->par_h);
+
     return GST_VAAPI_DECODER_STATUS_SUCCESS;
 }