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

[lance.lmwang at gmail.com]

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++;
+                    }
+                }
+            }
+        }
+
         nvenc_codec_specific_pic_params(avctx, &pic_params, sei_data, sei_count);
     } else {
         pic_params.encodePicFlags = NV_ENC_PIC_FLAG_EOS;
diff --git a/libavcodec/nvenc.h b/libavcodec/nvenc.h
index 7a415a4..f1adaeb 100644
--- a/libavcodec/nvenc.h
+++ b/libavcodec/nvenc.h
@@ -196,6 +196,7 @@ typedef struct NvencContext
     int coder;
     int b_ref_mode;
     int a53_cc;
+    int tc;
     int dpb_size;
 } NvencContext;
 
diff --git a/libavcodec/nvenc_hevc.c b/libavcodec/nvenc_hevc.c
index 7f12b56..6eef613 100644
--- a/libavcodec/nvenc_hevc.c
+++ b/libavcodec/nvenc_hevc.c
@@ -129,6 +129,7 @@ static const AVOption options[] = {
     { "each",         "",                                   0,                    AV_OPT_TYPE_CONST, { .i64 = 1 }, 0, 0,       VE, "b_ref_mode" },
     { "middle",       "",                                   0,                    AV_OPT_TYPE_CONST, { .i64 = 2 }, 0, 0,       VE, "b_ref_mode" },
 #endif
+    { "tc",        "Use timecode (if available)",           OFFSET(tc),           AV_OPT_TYPE_BOOL,  { .i64 = 1 }, 0, 1, VE },
     { "dpb_size",     "Specifies the DPB size used for encoding (0 means automatic)",
                                                             OFFSET(dpb_size),     AV_OPT_TYPE_INT,   { .i64 = 0 }, 0, INT_MAX, VE },
     { NULL }
-- 
1.8.3.1