[FFmpeg-devel] [PATCH v2 4/4] avcodec/nvenc: support for HEVC timecode passthrough

[Timo Rothenpieler]

On 17.06.2020 18:07, lance.lmwang at gmail.com wrote:
> From: Limin Wang <lance.lmwang at gmail.com>
> 
> Signed-off-by: Limin Wang <lance.lmwang at gmail.com>
> ---
> I failed to find any document about nvenc so that I can update for new option.
> 
>   libavcodec/nvenc.c      | 53 +++++++++++++++++++++++++++++++++++++++++++++++++
>   libavcodec/nvenc.h      |  1 +
>   libavcodec/nvenc_hevc.c |  1 +
>   3 files changed, 55 insertions(+)
> 
> diff --git a/libavcodec/nvenc.c b/libavcodec/nvenc.c
> index e4356ce..68b212a 100644
> --- a/libavcodec/nvenc.c
> +++ b/libavcodec/nvenc.c
> @@ -22,6 +22,8 @@
>   #include "config.h"
>   
>   #include "nvenc.h"
> +#include "hevc_sei.h"
> +#include "put_bits.h"
>   
>   #include "libavutil/hwcontext_cuda.h"
>   #include "libavutil/hwcontext.h"
> @@ -2068,6 +2070,15 @@ static void reconfig_encoder(AVCodecContext *avctx, const AVFrame *frame)
>       }
>   }
>   
> +static unsigned bcd2uint(uint8_t bcd)
> +{
> +    unsigned low  = bcd & 0xf;
> +    unsigned high = bcd >> 4;
> +    if (low > 9 || high > 9)
> +        return 0;
> +    return low + 10*high;
> +}
> +
>   int ff_nvenc_send_frame(AVCodecContext *avctx, const AVFrame *frame)
>   {
>       NVENCSTATUS nv_status;
> @@ -2156,6 +2167,48 @@ int ff_nvenc_send_frame(AVCodecContext *avctx, const AVFrame *frame)
>               }
>           }
>   
> +        if (ctx->tc && av_frame_get_side_data(frame, AV_FRAME_DATA_S12M_TIMECODE)) {
> +            AVFrameSideData *sd = av_frame_get_side_data(frame, AV_FRAME_DATA_S12M_TIMECODE);
> +            if (sd) {
> +                uint32_t *tc =  (uint32_t*)sd->data;
> +                int m = tc[0] & 3;
> +                if (tc) {
> +                    sei_data[sei_count].payloadSize = sizeof(uint32_t) * 4;
> +                    sei_data[sei_count].payloadType = HEVC_SEI_TYPE_TIME_CODE;
> +                    sei_data[sei_count].payload     = av_mallocz(sei_data[sei_count].payloadSize);
> +                    if (sei_data[sei_count].payload) {
> +                        PutBitContext pb;
> +
> +                        init_put_bits(&pb, sei_data[sei_count].payload, sei_data[sei_count].payloadSize);
> +                        put_bits(&pb, 2, m); // num_clock_ts
> +
> +                        for (int j = 1; j <= m; j++) {
> +                            uint32_t tcsmpte = tc[j];
> +                            unsigned hh   = bcd2uint(tcsmpte     & 0x3f);    // 6-bit hours
> +                            unsigned mm   = bcd2uint(tcsmpte>>8  & 0x7f);    // 7-bit minutes
> +                            unsigned ss   = bcd2uint(tcsmpte>>16 & 0x7f);    // 7-bit seconds
> +                            unsigned ff   = bcd2uint(tcsmpte>>24 & 0x3f);    // 6-bit frames
> +                            unsigned drop = tcsmpte & 1<<30 && !0;  // 1-bit drop if not arbitrary bit
> +
> +                            put_bits(&pb, 1, 1); // clock_timestamp_flag
> +                            put_bits(&pb, 1, 1); // units_field_based_flag
> +                            put_bits(&pb, 5, 0); // counting_type
> +                            put_bits(&pb, 1, 1); // full_timestamp_flag
> +                            put_bits(&pb, 1, 0); // discontinuity_flag
> +                            put_bits(&pb, 1, drop);
> +                            put_bits(&pb, 9, ff);
> +                            put_bits(&pb, 6, ss);
> +                            put_bits(&pb, 6, mm);
> +                            put_bits(&pb, 5, hh);
> +                            put_bits(&pb, 5, 0);
> +                        }
> +                        flush_put_bits(&pb);
> +                        sei_count++;
> +                    }
> +                }
> +            }
> +        }
> +

Does all this really have to be in nvenc? It looks very generic to me, 
and better put in some central location to be re-used by multiple codecs.