mpeg2: disable video cropping as picture_display_extension() is missing.

Disable video cropping in MPEG-2 codec because it is partially implemented
and actually because nobody implements it that way, and the standard spec
does not specify the display process either anyway.

Most notably, there are two possible use cases for sequence_display_extension()
horizontal_display_size & vertical_display_size: (i) guesstimating the
pixel-aspect-ratio, or (ii) implement some kind of span & scan process
in conjunction with picture_display_extension() information.

https://bugzilla.gnome.org/show_bug.cgi?id=704848

diff --git a/gst-libs/gst/vaapi/gstvaapidecoder_mpeg2.c b/gst-libs/gst/vaapi/gstvaapidecoder_mpeg2.c
index 7cf7821..711755f 100644 (file)
--- a/gst-libs/gst/vaapi/gstvaapidecoder_mpeg2.c
+++ b/gst-libs/gst/vaapi/gstvaapidecoder_mpeg2.c
@@ -242,6 +242,7 @@ struct _GstVaapiDecoderMpeg2Private {
     guint                       fps_n;
     guint                       fps_d;
     guint                       state;
+    GstVaapiRectangle           crop_rect;
     GstVaapiParserInfoMpeg2    *seq_hdr;
     GstVaapiParserInfoMpeg2    *seq_ext;
     GstVaapiParserInfoMpeg2    *seq_display_ext;
@@ -249,6 +250,7 @@ struct _GstVaapiDecoderMpeg2Private {
     GstVaapiParserInfoMpeg2    *gop;
     GstVaapiParserInfoMpeg2    *pic_hdr;
     GstVaapiParserInfoMpeg2    *pic_ext;
+    GstVaapiParserInfoMpeg2    *pic_display_ext;
     GstVaapiParserInfoMpeg2    *quant_matrix;
     GstVaapiParserInfoMpeg2    *slice_hdr;
     GstVaapiPicture            *current_picture;
@@ -298,6 +300,7 @@ gst_vaapi_decoder_mpeg2_close(GstVaapiDecoderMpeg2 *decoder)
     gst_vaapi_parser_info_mpeg2_replace(&priv->gop, NULL);
     gst_vaapi_parser_info_mpeg2_replace(&priv->pic_hdr, NULL);
     gst_vaapi_parser_info_mpeg2_replace(&priv->pic_ext, NULL);
+    gst_vaapi_parser_info_mpeg2_replace(&priv->pic_display_ext, NULL);
     gst_vaapi_parser_info_mpeg2_replace(&priv->quant_matrix, NULL);
     gst_vaapi_parser_info_mpeg2_replace(&priv->slice_hdr, NULL);
 
@@ -581,6 +584,7 @@ decode_sequence(GstVaapiDecoderMpeg2 *decoder, GstVaapiDecoderUnit *unit)
     gst_vaapi_parser_info_mpeg2_replace(&priv->seq_display_ext, NULL);
     gst_vaapi_parser_info_mpeg2_replace(&priv->seq_scalable_ext, NULL);
     gst_vaapi_parser_info_mpeg2_replace(&priv->quant_matrix, NULL);
+    gst_vaapi_parser_info_mpeg2_replace(&priv->pic_display_ext, NULL);
 
     priv->fps_n = seq_hdr->fps_n;
     priv->fps_d = seq_hdr->fps_d;
@@ -709,7 +713,22 @@ static GstVaapiDecoderStatus
 decode_sequence_display_ext(GstVaapiDecoderMpeg2 *decoder,
     GstVaapiDecoderUnit *unit)
 {
-    /* XXX: handle color primaries and cropping */
+    GstVaapiDecoderMpeg2Private * const priv = &decoder->priv;
+    GstMpegVideoSequenceDisplayExt *seq_display_ext;
+
+    seq_display_ext = priv->seq_display_ext ?
+        &priv->seq_display_ext->data.seq_display_ext : NULL;
+
+    /* Update cropping rectangle */
+    if (seq_display_ext) {
+        GstVaapiRectangle * const crop_rect = &priv->crop_rect;
+        crop_rect->x = 0;
+        crop_rect->y = 0;
+        crop_rect->width = seq_display_ext->display_horizontal_size;
+        crop_rect->height = seq_display_ext->display_vertical_size;
+    }
+
+    /* XXX: handle color primaries */
     return GST_VAAPI_DECODER_STATUS_SUCCESS;
 }
 
@@ -1473,14 +1492,12 @@ gst_vaapi_decoder_mpeg2_start_frame(GstVaapiDecoder *base_decoder,
     gst_vaapi_picture_unref(picture);
 
     /* Update cropping rectangle */
-    if (seq_display_ext) {
-        GstVaapiRectangle crop_rect;
-        crop_rect.x = 0;
-        crop_rect.y = 0;
-        crop_rect.width = seq_display_ext->display_horizontal_size;
-        crop_rect.height = seq_display_ext->display_vertical_size;
-        if (crop_rect.width <= priv->width && crop_rect.height <= priv->height)
-            gst_vaapi_picture_set_crop_rect(picture, &crop_rect);
+    /* XXX: handle picture_display_extension() */
+    if (seq_display_ext && priv->pic_display_ext) {
+        GstVaapiRectangle * const crop_rect = &priv->crop_rect;
+        if (crop_rect->x + crop_rect->width <= priv->width &&
+            crop_rect->y + crop_rect->height <= priv->height)
+            gst_vaapi_picture_set_crop_rect(picture, crop_rect);
     }
 
     status = ensure_quant_matrix(decoder, picture);