[FFmpeg-devel] [PATCH 1/2] ffplay: add -scaling_quality option for SDL

[Marton Balint]

On Tue, 4 Jun 2024, Ramiro Polla wrote:

> On Thu, May 30, 2024 at 11:36 PM Ramiro Polla <ramiro.polla at gmail.com> wrote:
>>
>> ---
>>  doc/ffplay.texi  | 2 ++
>>  fftools/ffplay.c | 6 +++++-
>>  2 files changed, 7 insertions(+), 1 deletion(-)
>>
>> diff --git a/doc/ffplay.texi b/doc/ffplay.texi
>> index 93f77eeece..60f883e159 100644
>> --- a/doc/ffplay.texi
>> +++ b/doc/ffplay.texi
>> @@ -72,6 +72,8 @@ as 100.
>>  Force format.
>>  @item -window_title @var{title}
>>  Set window title (default is the input filename).
>> + at item -scaling_quality @var{value}
>> +Set SDL_HINT_RENDER_SCALE_QUALITY value (default is "linear").
>>  @item -left @var{title}
>>  Set the x position for the left of the window (default is a centered window).
>>  @item -top @var{title}
>> diff --git a/fftools/ffplay.c b/fftools/ffplay.c
>> index b9d11eecee..75d2bec777 100644
>> --- a/fftools/ffplay.c
>> +++ b/fftools/ffplay.c
>> @@ -351,6 +351,7 @@ static int filter_nbthreads = 0;
>>  static int enable_vulkan = 0;
>>  static char *vulkan_params = NULL;
>>  static const char *hwaccel = NULL;
>> +static const char *scaling_quality = NULL;
>>
>>  /* current context */
>>  static int is_full_screen;
>> @@ -3683,6 +3684,7 @@ static const OptionDef options[] = {
>>      { "framedrop",          OPT_TYPE_BOOL,   OPT_EXPERT, { &framedrop }, "drop frames when cpu is too slow", "" },
>>      { "infbuf",             OPT_TYPE_BOOL,   OPT_EXPERT, { &infinite_buffer }, "don't limit the input buffer size (useful with realtime streams)", "" },
>>      { "window_title",       OPT_TYPE_STRING,          0, { &window_title }, "set window title", "window title" },
>> +    { "scaling_quality",    OPT_TYPE_STRING, OPT_EXPERT, { &scaling_quality }, "set SDL_HINT_RENDER_SCALE_QUALITY value (default=linear)", "value" },
>>      { "left",               OPT_TYPE_INT,    OPT_EXPERT, { &screen_left }, "set the x position for the left of the window", "x pos" },
>>      { "top",                OPT_TYPE_INT,    OPT_EXPERT, { &screen_top }, "set the y position for the top of the window", "y pos" },
>>      { "vf",                 OPT_TYPE_FUNC, OPT_FUNC_ARG | OPT_EXPERT, { .func_arg = opt_add_vfilter }, "set video filters", "filter_graph" },
>> @@ -3831,7 +3833,9 @@ int main(int argc, char **argv)
>>              }
>>          }
>>          window = SDL_CreateWindow(program_name, SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED, default_width, default_height, flags);
>> -        SDL_SetHint(SDL_HINT_RENDER_SCALE_QUALITY, "linear");
>> +        if (!scaling_quality)
>> +            scaling_quality = "linear";
>> +        SDL_SetHint(SDL_HINT_RENDER_SCALE_QUALITY, scaling_quality);
>>          if (!window) {
>>              av_log(NULL, AV_LOG_FATAL, "Failed to create window: %s", SDL_GetError());
>>              do_exit(NULL);
>> --
>> 2.39.2
>>
>
> Can anyone comment on this? I had a few doubts on this patch:
> - does the option name properly convey its functionality?
> - is the documentation too terse?
> - should we include the accepted values in the documentation, even
> though they are sdl-specific?

What is the benefit of having such option? I don't really see a strong use 
case for it. Also you want to propagate the scaling quality to placebo 
backend as well? Does it acutally make sense to do that?

Thanks,
Marton