[FFmpeg-devel] [PATCH v2] fftools/ffmpeg: add an option to forbid the fallback to software path when hardware init fails

[Linjie Fu]

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 "-fallback_forbid 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

 fftools/ffmpeg.c     | 2 ++
 fftools/ffmpeg.h     | 1 +
 fftools/ffmpeg_opt.c | 3 +++
 3 files changed, 6 insertions(+)

diff --git a/fftools/ffmpeg.c b/fftools/ffmpeg.c
index da4259a9a8..45694fef57 100644
--- a/fftools/ffmpeg.c
+++ b/fftools/ffmpeg.c
@@ -2890,6 +2890,8 @@ 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->fallback_forbid)
+        return AVERROR(EINVAL);
 
     return avcodec_default_get_buffer2(s, frame, flags);
 }
diff --git a/fftools/ffmpeg.h b/fftools/ffmpeg.h
index eb1eaf6363..67ddaeaaee 100644
--- a/fftools/ffmpeg.h
+++ b/fftools/ffmpeg.h
@@ -365,6 +365,7 @@ typedef struct InputStream {
     enum AVHWDeviceType hwaccel_device_type;
     char  *hwaccel_device;
     enum AVPixelFormat hwaccel_output_format;
+    int fallback_forbid;
 
     /* hwaccel context */
     void  *hwaccel_ctx;
diff --git a/fftools/ffmpeg_opt.c b/fftools/ffmpeg_opt.c
index d4851a2cd8..314e25565c 100644
--- a/fftools/ffmpeg_opt.c
+++ b/fftools/ffmpeg_opt.c
@@ -3600,6 +3600,9 @@ const OptionDef options[] = {
     { "autorotate",       HAS_ARG | OPT_BOOL | OPT_SPEC |
                           OPT_EXPERT | OPT_INPUT,                                { .off = OFFSET(autorotate) },
         "automatically insert correct rotate filters" },
+    { "fallback_forbid",  HAS_ARG | OPT_BOOL | OPT_SPEC |
+                          OPT_EXPERT | OPT_INPUT,                                { .off = OFFSET(fallback_forbid)},
+      "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 },
-- 
2.17.1