[FFmpeg-devel] [PATCH v2] avcodec/nvenc: add option to skip padding OBUs

[Cameron Gutman]

Some scenarios (such as game streaming or videoconferencing) may use CBR
to strictly cap the maximum encoded bitrate, but they don't mind the
bitrate falling below the target if the encoder doesn't need the
additional headroom.

Allow users to opt-out of filler data in CBR mode for those usecases
where it is unwanted.

Signed-off-by: Cameron Gutman <aicommander at gmail.com>
---
v2: Rebased to resolve conflicts against master
---
 libavcodec/nvenc.c     | 2 +-
 libavcodec/nvenc.h     | 1 +
 libavcodec/nvenc_av1.c | 2 ++
 3 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/libavcodec/nvenc.c b/libavcodec/nvenc.c
index 0f5e772b3e..0f2336b0ec 100644
--- a/libavcodec/nvenc.c
+++ b/libavcodec/nvenc.c
@@ -1624,7 +1624,7 @@ static av_cold int nvenc_setup_av1_config(AVCodecContext *avctx)
 
     av1->idrPeriod = cc->gopLength;
 
-    if (IS_CBR(cc->rcParams.rateControlMode)) {
+    if (ctx->filler_data && IS_CBR(cc->rcParams.rateControlMode)) {
         av1->enableBitstreamPadding = 1;
     }
 
diff --git a/libavcodec/nvenc.h b/libavcodec/nvenc.h
index e035e123c6..3431457422 100644
--- a/libavcodec/nvenc.h
+++ b/libavcodec/nvenc.h
@@ -309,6 +309,7 @@ typedef struct NvencContext
     int unidir_b;
     int split_encode_mode;
     int mdm, cll;
+    int filler_data;
 } NvencContext;
 
 int ff_nvenc_encode_init(AVCodecContext *avctx);
diff --git a/libavcodec/nvenc_av1.c b/libavcodec/nvenc_av1.c
index 01626113ab..c00817af7b 100644
--- a/libavcodec/nvenc_av1.c
+++ b/libavcodec/nvenc_av1.c
@@ -156,6 +156,8 @@ static const AVOption options[] = {
                                                             OFFSET(extra_sei),    AV_OPT_TYPE_BOOL,  { .i64 = 1 }, 0, 1, VE },
     { "a53cc",        "Use A53 Closed Captions (if available)", OFFSET(a53_cc),   AV_OPT_TYPE_BOOL,  { .i64 = 1 }, 0, 1, VE },
     { "s12m_tc",      "Use timecode (if available)",        OFFSET(s12m_tc),      AV_OPT_TYPE_BOOL,  { .i64 = 1 }, 0, 1, VE },
+    { "filler_data",  "Use filler data to ensure CBR bitrate is strictly adhered to",
+                                                            OFFSET(filler_data),  AV_OPT_TYPE_BOOL,  { .i64 = 1 }, 0, 1, VE },
 #ifdef NVENC_HAVE_H264_AND_AV1_TEMPORAL_FILTER
     { "tf_level",     "Specifies the strength of the temporal filtering",
                                                             OFFSET(tf_level),     AV_OPT_TYPE_INT,   { .i64 = -1 }, -1, INT_MAX, VE, .unit = "tf_level" },
-- 
2.49.0