[FFmpeg-devel] [PATCH] avcodec/nvenc: Use CBR filler data consistently across codecs
Zhao Zhili
quinkblack at foxmail.com
Sun Mar 30 18:46:02 EEST 2025
> On Mar 30, 2025, at 23:33, Kieran Kunhya via ffmpeg-devel <ffmpeg-devel at ffmpeg.org> wrote:
>
> On Sun, Mar 30, 2025 at 12:04 AM Cameron Gutman <aicommander at gmail.com <mailto:aicommander at gmail.com>> wrote:
>>
>> Previously, AV1 used filler data with CBR by default while H.264
>> and HEVC did not. Make this consistent by using filler data in
>> CBR mode across all codecs.
>>
>> Since there are valid reasons to use CBR with or without filler,
>> also add a cbr_padding option to allow users to opt out.
>>
>> Signed-off-by: Cameron Gutman <aicommander at gmail.com>
>> ---
>> libavcodec/nvenc.c | 16 +++++++++++++---
>> libavcodec/nvenc.h | 2 ++
>> libavcodec/nvenc_av1.c | 2 ++
>> libavcodec/nvenc_h264.c | 4 ++++
>> libavcodec/nvenc_hevc.c | 4 ++++
>> 5 files changed, 25 insertions(+), 3 deletions(-)
>>
>> diff --git a/libavcodec/nvenc.c b/libavcodec/nvenc.c
>> index 0f5e772b3e..41a4dc55f4 100644
>> --- a/libavcodec/nvenc.c
>> +++ b/libavcodec/nvenc.c
>> @@ -1304,7 +1304,12 @@ static av_cold int nvenc_setup_h264_config(AVCodecContext *avctx)
>> h264->idrPeriod = cc->gopLength;
>>
>> if (IS_CBR(cc->rcParams.rateControlMode)) {
>> - h264->outputBufferingPeriodSEI = 1;
>> + /* Older SDKs use outputBufferingPeriodSEI to control filler data */
>> + h264->outputBufferingPeriodSEI = ctx->cbr_padding;
>> +
>> +#ifdef NVENC_HAVE_FILLER_DATA
>> + h264->enableFillerDataInsertion = ctx->cbr_padding;
>> +#endif
>> }
>>
>> h264->outputPictureTimingSEI = 1;
>> @@ -1503,7 +1508,12 @@ static av_cold int nvenc_setup_hevc_config(AVCodecContext *avctx)
>> hevc->idrPeriod = cc->gopLength;
>>
>> if (IS_CBR(cc->rcParams.rateControlMode)) {
>> - hevc->outputBufferingPeriodSEI = 1;
>> + /* Older SDKs use outputBufferingPeriodSEI to control filler data */
>> + hevc->outputBufferingPeriodSEI = ctx->cbr_padding;
>> +
>> +#ifdef NVENC_HAVE_FILLER_DATA
>> + hevc->enableFillerDataInsertion = ctx->cbr_padding;
>> +#endif
>> }
>>
>> hevc->outputPictureTimingSEI = 1;
>> @@ -1625,7 +1635,7 @@ static av_cold int nvenc_setup_av1_config(AVCodecContext *avctx)
>> av1->idrPeriod = cc->gopLength;
>>
>> if (IS_CBR(cc->rcParams.rateControlMode)) {
>> - av1->enableBitstreamPadding = 1;
>> + av1->enableBitstreamPadding = ctx->cbr_padding;
>> }
>>
>> if (ctx->tile_cols >= 0)
>> diff --git a/libavcodec/nvenc.h b/libavcodec/nvenc.h
>> index e035e123c6..4b12846ed7 100644
>> --- a/libavcodec/nvenc.h
>> +++ b/libavcodec/nvenc.h
>> @@ -61,6 +61,7 @@ typedef void ID3D11Device;
>> #define NVENC_HAVE_MULTIPLE_REF_FRAMES
>> #define NVENC_HAVE_CUSTREAM_PTR
>> #define NVENC_HAVE_GETLASTERRORSTRING
>> +#define NVENC_HAVE_FILLER_DATA
>> #endif
>>
>> // SDK 10.0 compile time feature checks
>> @@ -309,6 +310,7 @@ typedef struct NvencContext
>> int unidir_b;
>> int split_encode_mode;
>> int mdm, cll;
>> + int cbr_padding;
>> } NvencContext;
>>
>> int ff_nvenc_encode_init(AVCodecContext *avctx);
>> diff --git a/libavcodec/nvenc_av1.c b/libavcodec/nvenc_av1.c
>> index 01626113ab..b1b95672f2 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 },
>> + { "cbr_padding", "Pad the bitstream to ensure bitrate does not drop below the target in CBR mode",
>> + OFFSET(cbr_padding), 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" },
>> diff --git a/libavcodec/nvenc_h264.c b/libavcodec/nvenc_h264.c
>> index 21d25d643a..4845d0422d 100644
>> --- a/libavcodec/nvenc_h264.c
>> +++ b/libavcodec/nvenc_h264.c
>> @@ -231,6 +231,10 @@ static const AVOption options[] = {
>> OFFSET(max_slice_size), AV_OPT_TYPE_INT, { .i64 = 0 }, 0, INT_MAX, VE },
>> { "constrained-encoding", "Enable constrainedFrame encoding where each slice in the constrained picture is independent of other slices",
>> OFFSET(constrained_encoding), AV_OPT_TYPE_BOOL, { .i64 = 0 }, 0, 1, VE },
>> +#ifdef NVENC_HAVE_FILLER_DATA
>> + { "cbr_padding", "Pad the bitstream to ensure bitrate does not drop below the target in CBR mode",
>> + OFFSET(cbr_padding), AV_OPT_TYPE_BOOL, { .i64 = 1 }, 0, 1, VE },
>> +#endif
>> #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" },
>> diff --git a/libavcodec/nvenc_hevc.c b/libavcodec/nvenc_hevc.c
>> index c74eca9bb3..8648f4f3a9 100644
>> --- a/libavcodec/nvenc_hevc.c
>> +++ b/libavcodec/nvenc_hevc.c
>> @@ -206,6 +206,10 @@ static const AVOption options[] = {
>> OFFSET(max_slice_size), AV_OPT_TYPE_INT, { .i64 = 0 }, 0, INT_MAX, VE },
>> { "constrained-encoding", "Enable constrainedFrame encoding where each slice in the constrained picture is independent of other slices",
>> OFFSET(constrained_encoding), AV_OPT_TYPE_BOOL, { .i64 = 0 }, 0, 1, VE },
>> +#ifdef NVENC_HAVE_FILLER_DATA
>> + { "cbr_padding", "Pad the bitstream to ensure bitrate does not drop below the target in CBR mode",
>> + OFFSET(cbr_padding), AV_OPT_TYPE_BOOL, { .i64 = 1 }, 0, 1, VE },
>> +#endif
>> #ifdef NVENC_HAVE_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
>
>
> This should be off by default in FFmpeg. We don't do this in any other encoder.
I agree.
>
> Kieran
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