On Wed, 29 Apr 2020, Linjie Fu wrote:

It would be 200kbps bitrate with gop size = 12 by default
which generated too many IDR frames in rather low bit rate.
The quality would be poor.

Set these default values to -1 to check whether it's specified
by user explicitly.

Use 2Mbps bitrate as nvenc sugguested, and leave gop size
untouched in libopenh264.

Signed-off-by: Linjie Fu <linjie...@intel.com>
---
libavcodec/libopenh264enc.c | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/libavcodec/libopenh264enc.c b/libavcodec/libopenh264enc.c
index 265eb9c..245752d 100644
--- a/libavcodec/libopenh264enc.c
+++ b/libavcodec/libopenh264enc.c
@@ -37,6 +37,8 @@
#define SM_SIZELIMITED_SLICE SM_DYN_SLICE
#endif

+#define TARGET_BITRATE_DEFAULT 2*1000*1000
+
typedef struct SVCContext {
    const AVClass *av_class;
    ISVCEncoder *encoder;
@@ -132,7 +134,7 @@ FF_ENABLE_DEPRECATION_WARNINGS
    param.fMaxFrameRate              = 1/av_q2d(avctx->time_base);
    param.iPicWidth                  = avctx->width;
    param.iPicHeight                 = avctx->height;
-    param.iTargetBitrate             = avctx->bit_rate;
+    param.iTargetBitrate             = avctx->bit_rate > 0 ? avctx->bit_rate : 
TARGET_BITRATE_DEFAULT;
    param.iMaxBitrate                = FFMAX(avctx->rc_max_rate, 
avctx->bit_rate);
    param.iRCMode                    = RC_QUALITY_MODE;
    if (avctx->qmax >= 0)
@@ -147,7 +149,8 @@ FF_ENABLE_DEPRECATION_WARNINGS
    param.bEnableFrameSkip           = s->skip_frames;
    param.bEnableLongTermReference   = 0;
    param.iLtrMarkPeriod             = 30;
-    param.uiIntraPeriod              = avctx->gop_size;
+    if (avctx->gop_size >= 0)
+        param.uiIntraPeriod          = avctx->gop_size;
#if OPENH264_VER_AT_LEAST(1, 4)
    param.eSpsPpsIdStrategy          = CONSTANT_ID;
#else
@@ -336,6 +339,8 @@ static int svc_encode_frame(AVCodecContext *avctx, AVPacket 
*avpkt,
}

static const AVCodecDefault svc_enc_defaults[] = {
+    { "b",         "0"     },
+    { "g",         "-1"    },
    { "qmin",      "-1"    },
    { "qmax",      "-1"    },
    { NULL },
--
2.7.4

LGTM

// Martin

_______________________________________________
ffmpeg-devel mailing list
ffmpeg-devel@ffmpeg.org
https://ffmpeg.org/mailman/listinfo/ffmpeg-devel

To unsubscribe, visit link above, or email
ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".

Reply via email to