[FFmpeg-devel] [PATCH v3] fftools/ffmpeg: add an option to forbid the fallback to software path when hardware init fails

[Li, Zhong]

> From: ffmpeg-devel [mailto:ffmpeg-devel-bounces at ffmpeg.org] On Behalf
> Of Linjie Fu
> Sent: Friday, November 9, 2018 5:06 PM
> To: ffmpeg-devel at ffmpeg.org
> Cc: Fu, Linjie <linjie.fu at intel.com>
> Subject: [FFmpeg-devel] [PATCH v3] fftools/ffmpeg: add an option to forbid
> the fallback to software path when hardware init fails
> 
> Currently ff_get_format will go through all usable choices if the chosen
> format was not supported. It will fallback to software path if the hardware
> init fails.
> 
> Provided an option "-require_hwaccel 1" in user-code to detect
> frame->format and hwaccel_get_buffer in get_buffer. If hardware init fails,
> returns an error.

Would better if add commit message it is to track ticket #7519 

> Signed-off-by: Linjie Fu <linjie.fu at intel.com>
> ---
> [v2] detect hardware init failures in get_buffer and modify in user-code [v3]
> changed the option name, add error message
> 
>  fftools/ffmpeg.c     | 4 ++++
>  fftools/ffmpeg.h     | 3 +++
>  fftools/ffmpeg_opt.c | 4 ++++
>  3 files changed, 11 insertions(+)
> 
> diff --git a/fftools/ffmpeg.c b/fftools/ffmpeg.c index
> da4259a9a8..113ab6312a 100644
> --- a/fftools/ffmpeg.c
> +++ b/fftools/ffmpeg.c
> @@ -2890,6 +2890,10 @@ static int get_buffer(AVCodecContext *s,
> AVFrame *frame, int flags)
> 
>      if (ist->hwaccel_get_buffer && frame->format ==
> ist->hwaccel_pix_fmt)
>          return ist->hwaccel_get_buffer(s, frame, flags);
> +    else if (ist->require_hwaccel) {
> +        av_log(s, AV_LOG_ERROR, "Hardware acceleration is required
> and will not fallback to try software path.\n");
> +        return AVERROR(EINVAL);
> +    }
> 
>      return avcodec_default_get_buffer2(s, frame, flags);  } diff --git
> a/fftools/ffmpeg.h b/fftools/ffmpeg.h index eb1eaf6363..a5c85daa67
> 100644
> --- a/fftools/ffmpeg.h
> +++ b/fftools/ffmpeg.h
> @@ -133,6 +133,8 @@ typedef struct OptionsContext {
>      int        nb_hwaccel_output_formats;
>      SpecifierOpt *autorotate;
>      int        nb_autorotate;
> +    SpecifierOpt *require_hwaccel;
> +    int        nb_require_hwaccel;
> 
>      /* output options */
>      StreamMap *stream_maps;
> @@ -365,6 +367,7 @@ typedef struct InputStream {
>      enum AVHWDeviceType hwaccel_device_type;
>      char  *hwaccel_device;
>      enum AVPixelFormat hwaccel_output_format;
> +    int require_hwaccel;
> 
>      /* hwaccel context */
>      void  *hwaccel_ctx;
> diff --git a/fftools/ffmpeg_opt.c b/fftools/ffmpeg_opt.c index
> d4851a2cd8..6890bb7fcf 100644
> --- a/fftools/ffmpeg_opt.c
> +++ b/fftools/ffmpeg_opt.c
> @@ -730,6 +730,7 @@ static void add_input_streams(OptionsContext *o,
> AVFormatContext *ic)
>          ist->autorotate = 1;
>          MATCH_PER_STREAM_OPT(autorotate, i, ist->autorotate, ic, st);
> 
> +        MATCH_PER_STREAM_OPT(require_hwaccel, i,
> ist->require_hwaccel,
> + ic, st);
>          MATCH_PER_STREAM_OPT(codec_tags, str, codec_tag, ic, st);
>          if (codec_tag) {
>              uint32_t tag = strtol(codec_tag, &next, 0); @@ -3600,6
> +3601,9 @@ const OptionDef options[] = {
>      { "autorotate",       HAS_ARG | OPT_BOOL | OPT_SPEC |
>                            OPT_EXPERT | OPT_INPUT,
> { .off = OFFSET(autorotate) },
>          "automatically insert correct rotate filters" },
> +    { "require_hwaccel",  HAS_ARG | OPT_BOOL | OPT_SPEC |
> +                          OPT_EXPERT | OPT_INPUT,


> { .off = OFFSET(require_hwaccel)},
> +      "forbid the fallback to default software path when hardware init
> + fails"},

I would like to see a name like "force_hwaccel". HWACEEL is already required with the option "hwaccel" though it is not to force HW path.