[FFmpeg-devel] [PATCH v2] avcodec/v4l2_m2m_enc: Support changing qmin/qmax

[Andriy Gelman]

From: Andriy Gelman <andriy.gelman at gmail.com>

Hard coded parameters for qmin and qmax are currently used to initialize
v4l2_m2m device. This commit uses values from avctx->{qmin,qmax} if they
are set.

Signed-off-by: Andriy Gelman <andriy.gelman at gmail.com>
---
 libavcodec/v4l2_m2m_enc.c | 33 +++++++++++++++++++++++++++++++--
 1 file changed, 31 insertions(+), 2 deletions(-)

diff --git a/libavcodec/v4l2_m2m_enc.c b/libavcodec/v4l2_m2m_enc.c
index 8059e3bb48f..318be0d3379 100644
--- a/libavcodec/v4l2_m2m_enc.c
+++ b/libavcodec/v4l2_m2m_enc.c
@@ -31,10 +31,25 @@
 #include "v4l2_context.h"
 #include "v4l2_m2m.h"
 #include "v4l2_fmt.h"
+#include "internal.h"
 
 #define MPEG_CID(x) V4L2_CID_MPEG_VIDEO_##x
 #define MPEG_VIDEO(x) V4L2_MPEG_VIDEO_##x
 
+#define CLIP_MIN_MAX(in, min_val, max_val, name, logctx)    \
+    do {                                                    \
+        if ((in) < (min_val)) {                             \
+            av_log((logctx), AV_LOG_WARNING,                \
+                   "Adjusted: " name " (%d)\n", (min_val)); \
+            in = min_val;                                   \
+        }                                                   \
+        if ((in) > (max_val)) {                             \
+            av_log((logctx), AV_LOG_WARNING,                \
+                   "Adjusted: " name " (%d)\n", (max_val)); \
+            (in) = (max_val);                               \
+        }                                                   \
+    } while (0)
+
 static inline void v4l2_set_timeperframe(V4L2m2mContext *s, unsigned int num, unsigned int den)
 {
     struct v4l2_streamparm parm = { 0 };
@@ -232,8 +247,15 @@ static int v4l2_prepare_encoder(V4L2m2mContext *s)
         return 0;
     }
 
-    if (qmin != avctx->qmin || qmax != avctx->qmax)
-        av_log(avctx, AV_LOG_WARNING, "Encoder adjusted: qmin (%d), qmax (%d)\n", qmin, qmax);
+    if (avctx->qmin >= 0) {
+        CLIP_MIN_MAX(avctx->qmin, qmin, qmax, "qmin", avctx);
+        qmin = avctx->qmin;
+    }
+
+    if (avctx->qmax >= 0) {
+        CLIP_MIN_MAX(avctx->qmax, qmin, qmax, "qmax", avctx);
+        qmax = avctx->qmax;
+    }
 
     v4l2_set_ext_ctrl(s, qmin_cid, qmin, "minimum video quantizer scale");
     v4l2_set_ext_ctrl(s, qmax_cid, qmax, "maximum video quantizer scale");
@@ -349,6 +371,12 @@ static const AVOption options[] = {
     { NULL },
 };
 
+static const AVCodecDefault v4l2_m2m_defaults[] = {
+    { "qmin", "-1" },
+    { "qmax", "-1" },
+    { NULL },
+};
+
 #define M2MENC_CLASS(NAME) \
     static const AVClass v4l2_m2m_ ## NAME ## _enc_class = { \
         .class_name = #NAME "_v4l2m2m_encoder", \
@@ -370,6 +398,7 @@ static const AVOption options[] = {
         .send_frame     = v4l2_send_frame, \
         .receive_packet = v4l2_receive_packet, \
         .close          = v4l2_encode_close, \
+        .defaults       = v4l2_m2m_defaults, \
         .capabilities   = AV_CODEC_CAP_HARDWARE | AV_CODEC_CAP_DELAY, \
         .wrapper_name   = "v4l2m2m", \
     };
-- 
2.24.1