[FFmpeg-devel] [PATCH 1/4] Correctly set Display Aspect Ratio in nvenc.

[Philip Langdale]

The encoder writes the display aspect ratio into the output frames, which a
good player will respect, so let's make sure it's correct.

The 1.02 scale factor is black magic, but produces correct results. I don't
know what nvenc is doing.

Signed-off-by: Philip Langdale <philipl at overt.org>
---
 libavcodec/libnvenc.c  | 2 ++
 libavcodec/libnvenc.h  | 2 ++
 libavcodec/nvencoder.c | 8 ++++----
 3 files changed, 8 insertions(+), 4 deletions(-)

diff --git a/libavcodec/libnvenc.c b/libavcodec/libnvenc.c
index d81e04a..6ba150e 100644
--- a/libavcodec/libnvenc.c
+++ b/libavcodec/libnvenc.c
@@ -129,6 +129,8 @@ static av_cold int ff_libnvenc_init(AVCodecContext *avctx)
     // Basic
     nvenc_ctx->nvenc_cfg.width        = avctx->width;
     nvenc_ctx->nvenc_cfg.height       = avctx->height;
+    nvenc_ctx->nvenc_cfg.darWidth     = 1024 * avctx->width * avctx->sample_aspect_ratio.num / avctx->sample_aspect_ratio.den;
+    nvenc_ctx->nvenc_cfg.darHeight    = 1024 * avctx->height * 1.02;
     nvenc_ctx->nvenc_cfg.frameRateNum = avctx->time_base.den;
     nvenc_ctx->nvenc_cfg.frameRateDen = avctx->time_base.num * avctx->ticks_per_frame;
 
diff --git a/libavcodec/libnvenc.h b/libavcodec/libnvenc.h
index 42718a2..63b5d67 100644
--- a/libavcodec/libnvenc.h
+++ b/libavcodec/libnvenc.h
@@ -48,6 +48,8 @@ typedef struct nvenc_cfg_t
     // Basic
     uint32_t            width;
     uint32_t            height;
+    uint32_t            darWidth;
+    uint32_t            darHeight;
     uint32_t            frameRateNum;
     uint32_t            frameRateDen;
 
diff --git a/libavcodec/nvencoder.c b/libavcodec/nvencoder.c
index 06eb68b..f1d432f 100644
--- a/libavcodec/nvencoder.c
+++ b/libavcodec/nvencoder.c
@@ -517,8 +517,8 @@ static bool initialize(nvencoder_t *nvenc, nvenc_cfg_t *nvenc_cfg)
     nvenc->init_params.presetGUID         = NV_ENC_PRESET_HQ_GUID;
     nvenc->init_params.encodeWidth        = nvenc_cfg->width;
     nvenc->init_params.encodeHeight       = nvenc_cfg->height;
-    nvenc->init_params.darWidth           = nvenc_cfg->width;
-    nvenc->init_params.darHeight          = nvenc_cfg->height;
+    nvenc->init_params.darWidth           = nvenc_cfg->darWidth;
+    nvenc->init_params.darHeight          = nvenc_cfg->darHeight;
     nvenc->init_params.frameRateNum       = nvenc_cfg->frameRateNum;
     nvenc->init_params.frameRateDen       = nvenc_cfg->frameRateDen;
     nvenc->init_params.enableEncodeAsync  = 0;
@@ -696,8 +696,8 @@ static bool reconfig(nvencoder_t *nvenc, nvenc_cfg_t *nvenc_cfg)
     // Update initial encoder parameters that likely changed
     nvenc->init_params.encodeWidth  = nvenc_cfg->width;
     nvenc->init_params.encodeHeight = nvenc_cfg->height;
-    nvenc->init_params.darWidth     = nvenc_cfg->width;
-    nvenc->init_params.darWidth     = nvenc_cfg->height;
+    nvenc->init_params.darWidth     = nvenc_cfg->darWidth;
+    nvenc->init_params.darHeight    = nvenc_cfg->darHeight;
     nvenc->init_params.frameRateNum = nvenc_cfg->frameRateNum;
     nvenc->init_params.frameRateDen = nvenc_cfg->frameRateDen;
     nvenc->init_params.encodeConfig->rcParams.averageBitRate = nvenc_cfg->avgBitRate;
-- 
2.1.0