[Spice-devel] [PATCH 1/2] gstreamer-encoder: Use NV12 as the default vpp conversion format

[Frediano Ziglio]

Il giorno ven 15 set 2023 alle ore 01:33 Vivek Kasireddy
<vivek.kasireddy at intel.com> ha scritto:
>
> From: Hazwan Arif Mazlan <hazwan.arif.mazlan at intel.com>
>
> Using NV12 as the output format for the videoconvert element would
> allow us to pair a s/w based encoder with a h/w based decoder for
> decoding the stream as most h/w based decoders only accept NV12 as
> the input format given its popularity.
>

I don't fully understand the rationale. Yes, the h/w codecs usually
would convert this to NV12 however should not this be done by
gstreamer instead?
Surely YUV conversion is useful but what if a software conversion
would like to use Y444 instead? With NV12 you would lose image
quality.
Isn't gstreamer supposed to come out with the best combination?
Maybe it would be easier to have a more complete pipeline string
instead specified for each codec?

> Cc: Frediano Ziglio <freddy77 at gmail.com>
> Cc: Dongwon Kim <dongwon.kim at intel.com>
> Signed-off-by: Hazwan Arif Mazlan <hazwan.arif.mazlan at intel.com>
> Signed-off-by: Jin Chung Teng <jin.chung.teng at intel.com>
> Signed-off-by: Vivek Kasireddy <vivek.kasireddy at intel.com>
> ---
>  server/gstreamer-encoder.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/server/gstreamer-encoder.c b/server/gstreamer-encoder.c
> index d8af91f1..057509b5 100644
> --- a/server/gstreamer-encoder.c
> +++ b/server/gstreamer-encoder.c
> @@ -918,7 +918,7 @@ static gboolean create_pipeline(SpiceGstEncoder *encoder)
>  #ifdef HAVE_GSTREAMER_0_10
>      const gchar *converter = "ffmpegcolorspace";
>  #else
> -    const gchar *converter = "videoconvert";
> +    const gchar *converter = "videoconvert ! video/x-raw,format=NV12";
>  #endif
>      const gchar* gstenc_name = get_gst_codec_name(encoder);
>      if (!gstenc_name) {


Frediano