Re: [ptxdist] [PATCH 2/2] gst-libav1: fix avvideocompare element

[Michael Olbrich <m.olbrich@pengutronix.de>]

On Thu, Nov 27, 2025 at 11:51:03AM +0100, Michael Olbrich wrote:
> On Fri, Nov 14, 2025 at 03:20:22PM +0100, Sven Püschel wrote:
> > With the update to FFmpeg 8.0 the avvideocompare element from GStreamer
> > doesn't emit statistics anymore. Add a patch to fix the underlying
> > issue of missing colorimetry information.
> > 
> > Fixes: 254f9c65f4dd ("ffmpeg: version bump 7.1.1 -> 8.0")
> > Signed-off-by: Sven Püschel <s.pueschel@pengutronix.de>
> > ---
> >  ...-avvidcmp-set-colorimetry-on-AVFrame.patch | 75 +++++++++++++++++++
> >  patches/gst-libav-1.26.0/series               |  4 +
> >  2 files changed, 79 insertions(+)
> >  create mode 100644 patches/gst-libav-1.26.0/0001-gst-libav-avvidcmp-set-colorimetry-on-AVFrame.patch
> >  create mode 100644 patches/gst-libav-1.26.0/series
> 
> The current version in ptxdist 1.26.7 and I have a pending update to
> 1.26.8.

Ignore this. I didn't see the v2 when I wrote this.

Michael

> > 
> > diff --git a/patches/gst-libav-1.26.0/0001-gst-libav-avvidcmp-set-colorimetry-on-AVFrame.patch b/patches/gst-libav-1.26.0/0001-gst-libav-avvidcmp-set-colorimetry-on-AVFrame.patch
> > new file mode 100644
> > index 000000000..1a499537d
> > --- /dev/null
> > +++ b/patches/gst-libav-1.26.0/0001-gst-libav-avvidcmp-set-colorimetry-on-AVFrame.patch
> > @@ -0,0 +1,75 @@
> > +From: =?UTF-8?q?Sven=20P=C3=BCschel?= <s.pueschel@pengutronix.de>
> > +Date: Fri, 14 Nov 2025 10:50:51 +0100
> > +Subject: [PATCH] gst-libav: avvidcmp: set colorimetry on AVFrame
> > +MIME-Version: 1.0
> > +Content-Type: text/plain; charset=UTF-8
> > +Content-Transfer-Encoding: 8bit
> > +
> > +Set the colorimetry on AVFrame based on the GstVideoFrame values.
> > +This properly maps potential colorimetry information to libav.
> > +
> > +Furthermore this fixes the avvideocompare element when used with
> > +FFmpeg 8.0. When comparing video frames FFmpeg also uses the scale
> > +filter. This has been reworked to use a new API [1], which checks
> > +that the color primaries and transfer characteristics are not set
> > +to RESERVED, which is the default 0 value. This causes the ff_test_fmt
> > +function to fail which in turn causes the avvideocompare element to fail.
> > +
> > +The implementation is copied from gst_ffmpeg_videoinfo_to_context, but
> > +the color range has been adopted to also map the unknown range to
> > +unspecified, similar to how gst_ffmpeg_videoinfo_to_context maps
> > +AVCOL_RANGE_UNSPECIFIED to GST_VIDEO_COLOR_RANGE_UNKNOWN.
> > +
> > +This was tested with FFmpeg 8.0 and the following sample pipeline:
> > +
> > +  gst-launch-1.0 videotestsrc num-buffers=100          \
> > +    ! video/x-raw,format=NV12                          \
> > +    ! videobalance brightness=0.005 hue=0.005          \
> > +    ! avvideocompare method=psnr stats-file=- name=cmp \
> > +    ! fakesink videotestsrc ! video/x-raw,format=NV12  \
> > +    ! cmp.
> > +
> > +Without the patch it doesn't generate any stats output and when called
> > +with GST_DEBUG=3 it shows the following errors for each frame:
> > +
> > +  Unsupported input (Operation not supported):
> > +  fmt:nv12 csp:gbr prim:reserved trc:reserved -> fmt:yuv420p csp:unknown prim:reserved trc:reserved
> > +
> > +[1] https://github.com/FFmpeg/FFmpeg/commit/04ce01df0bb2d66e143bcfcea439afc2a1b8d96e
> > +
> > +Upstream-Status: Submitted [https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/10090]
> > +Signed-off-by: Sven Püschel <s.pueschel@pengutronix.de>
> > +---
> > + ext/libav/gstavvidcmp.c | 19 +++++++++++++++++++
> > + 1 file changed, 19 insertions(+)
> > +
> > +diff --git a/ext/libav/gstavvidcmp.c b/ext/libav/gstavvidcmp.c
> > +index 9fab0238935e..a5375e081a48 100644
> > +--- a/ext/libav/gstavvidcmp.c
> > ++++ b/ext/libav/gstavvidcmp.c
> > +@@ -619,6 +619,25 @@ _fill_avpicture (GstFFMpegVidCmp * self, AVFrame * picture,
> > +   picture->width = GST_VIDEO_FRAME_WIDTH (vframe);
> > +   picture->height = GST_VIDEO_FRAME_HEIGHT (vframe);
> > +   picture->format = self->pixfmt;
> > ++
> > ++  picture->color_primaries =
> > ++      gst_video_color_primaries_to_iso (vframe->info.colorimetry.primaries);
> > ++  picture->color_trc =
> > ++      gst_video_transfer_function_to_iso (vframe->info.colorimetry.transfer);
> > ++  picture->colorspace =
> > ++      gst_video_color_matrix_to_iso (vframe->info.colorimetry.matrix);
> > ++
> > ++  switch (vframe->info.colorimetry.range) {
> > ++    case GST_VIDEO_COLOR_RANGE_0_255:
> > ++      picture->color_range = AVCOL_RANGE_JPEG;
> > ++      break;
> > ++    case GST_VIDEO_COLOR_RANGE_16_235:
> > ++      picture->color_range = AVCOL_RANGE_MPEG;
> > ++      break;
> > ++    case GST_VIDEO_COLOR_RANGE_UNKNOWN:
> > ++      picture->color_range = AVCOL_RANGE_UNSPECIFIED;
> > ++      break;
> > ++  }
> > + }
> > + 
> > + static GstFlowReturn
> > diff --git a/patches/gst-libav-1.26.0/series b/patches/gst-libav-1.26.0/series
> > new file mode 100644
> > index 000000000..93a96c141
> > --- /dev/null
> > +++ b/patches/gst-libav-1.26.0/series
> > @@ -0,0 +1,4 @@
> > +# generated by git-ptx-patches
> > +#tag:base --start-number 1
> > +0001-gst-libav-avvidcmp-set-colorimetry-on-AVFrame.patch
> > +# 4a2c6890c0534fedb7f6c1a8e71acbd7  - git-ptx-patches magic
> > -- 
> > 2.47.3
> > 
> > 
> > 
> 
> -- 
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> 
> 

-- 
Pengutronix e.K.                           |                             |
Steuerwalder Str. 21                       | http://www.pengutronix.de/  |
31137 Hildesheim, Germany                  | Phone: +49-5121-206917-0    |
Amtsgericht Hildesheim, HRA 2686           | Fax:   +49-5121-206917-5555 |