[FFmpeg-devel] [PATCH v3] 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 "-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);
+    }
 
     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 },
-- 
2.17.1