[FFmpeg-devel] [PATCH v3] fftools/ffmpeg: add an option to forbid the fallback to software path when hardware init fails
Mark Thompson
sw at jkqxz.net
Sun Nov 11 17:08:34 EET 2018
On 09/11/18 09:05, Linjie Fu wrote:
> 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.
>
> 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);
> + }
Um, doesn't this just break every hardware case except QSV? The hwaccel_get_buffer function is only used for QSV, and will be unset for any other cases. (In fact, I don't think it does anything useful there anyway - maybe it can be removed completely, I'll have a look.)
I think the right place to make this decision (to force a hardware format) is in get_format(), rather than after when the decoder is already configured - this avoids cases where the format you actually wanted was available but you didn't pick it and then fail later. I had a patch lying around for another purpose which gives you some support for this, just sent if you'd like to have a look.
>
> 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"},
>
> /* audio options */
> { "aframes", OPT_AUDIO | HAS_ARG | OPT_PERFILE | OPT_OUTPUT, { .func_arg = opt_audio_frames },
>
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