[vlc-devel] [PATCH] core: add "decoder-hw" bool option

[Thomas Guillem]

Enabled by default, this option be used to disable hardware decoders (with
"--no-decoder-hw"). This option can be set on input/media items and will be
forwarded to the decoder via the input_thread_t.

To disable hardware decoders, the core decoder have to disable decoder devices.
---
 src/input/decoder.c | 8 +++++++-
 src/libvlc-module.c | 6 ++++++
 2 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/src/input/decoder.c b/src/input/decoder.c
index 17a36df3c9b..03d92c429c2 100644
--- a/src/input/decoder.c
+++ b/src/input/decoder.c
@@ -129,6 +129,7 @@ struct decoder_owner
     vout_thread_t   *p_vout;
     enum vlc_vout_order vout_order;
     bool            vout_thread_started;
+    bool            use_hw;
 
     /* -- Theses variables need locking on read *and* write -- */
     /* Preroll */
@@ -615,8 +616,12 @@ static vlc_decoder_device * ModuleThread_GetDecoderDevice( decoder_t *p_dec )
     struct decoder_owner *p_owner = dec_get_owner( p_dec );
 
     enum vlc_vout_order vout_order;
+
+    /* Requesting a decoder device will automatically enable hw decoding */
     vlc_decoder_device *dec_device = NULL;
-    int created_vout = CreateVoutIfNeeded(p_owner, NULL, &vout_order, &dec_device);
+    vlc_decoder_device **dec_device_ptr = p_owner->use_hw ? &dec_device : NULL;
+
+    int created_vout = CreateVoutIfNeeded(p_owner, NULL, &vout_order, dec_device_ptr);
     if (created_vout == -1)
     {
         if ( dec_device )
@@ -1848,6 +1853,7 @@ static struct decoder_owner * CreateDecoder( vlc_object_t *p_parent,
     p_owner->p_aout = NULL;
     p_owner->p_vout = NULL;
     p_owner->vout_thread_started = false;
+    p_owner->use_hw = var_InheritBool( p_parent, "decoder-hw" );
     p_owner->i_spu_channel = VOUT_SPU_CHANNEL_INVALID;
     p_owner->i_spu_order = 0;
     p_owner->p_sout = p_sout;
diff --git a/src/libvlc-module.c b/src/libvlc-module.c
index 1e733662cf6..9839a8274a9 100644
--- a/src/libvlc-module.c
+++ b/src/libvlc-module.c
@@ -968,6 +968,11 @@ static const char *const ppsz_prefres[] = {
     "before trying the other ones. Only advanced users should " \
     "alter this option as it can break playback of all your streams." )
 
+#define DECODER_HW_TEXT N_("Enable hardware decoders")
+#define DECODER_HW_LONGTEXT N_( \
+    "This will enable hardware decoders. VLC will fallback automatically to " \
+    "software decoders in case of hardware decoder failure." )
+
 #define ENCODER_TEXT N_("Preferred encoders list")
 #define ENCODER_LONGTEXT N_( \
     "This allows you to select a list of encoders that VLC will use in " \
@@ -2044,6 +2049,7 @@ vlc_module_begin ()
     add_category_hint(N_("Decoders"), CODEC_CAT_LONGTEXT)
     add_string( "codec", NULL, CODEC_TEXT,
                 CODEC_LONGTEXT, true )
+    add_bool( "decoder-hw", true, DECODER_HW_TEXT, DECODER_HW_LONGTEXT, true )
     add_string( "encoder",  NULL, ENCODER_TEXT,
                 ENCODER_LONGTEXT, true )
     add_module("dec-dev", "decoder device", "any", DEC_DEV_TEXT, DEC_DEV_LONGTEXT)
-- 
2.20.1