Add support for bitrate control

libavdevice/v4l2.c

@@ -67,6 +67,10 @@ static const int desired_video_buffers = 256;
  */
 #define V4L_TS_CONVERT_READY V4L_TS_DEFAULT
 
+
+#define UVC_IFPERIOD_DEFAULT 10000
+#define UVC_BITRATE_DEFAULT 3000000
+
 struct video_data {
     AVClass *class;
     int fd;
@@ -109,37 +113,6 @@ struct buff_data {
     int index;
 };
 
-void print_probe_commit(uvcx_video_config_probe_commit_t * probe);
-void print_probe_commit(uvcx_video_config_probe_commit_t * probe) {
-  printf("Frame interval: %d", probe->dwFrameInterval);
-  printf("\nBit rate : %d", probe->dwBitRate);
-  printf("\nHints : %X", probe->bmHints);
-  printf("\nConfiguration index : %d", probe->wConfigurationIndex);
-  printf("\nWidth : %d", probe->wWidth);
-  printf("\nHeight : %d", probe->wHeight);
-  printf("\nSlice units : %d", probe->wSliceUnits);
-  printf("\nSlice mode : %X", probe->wSliceMode);
-  printf("\nProfile : %X", probe->wProfile);
-  printf("\nIFrame Period : %d ms", probe->wIFramePeriod);
-  printf("\nEstimated video delay : %d ms", probe->wEstimatedVideoDelay);
-  printf("\nEstimated max config delay : %d ms", probe->wEstimatedMaxConfigDelay);
-  printf("\nUsage type : %X", probe->bUsageType);
-  printf("\nRate control mode : %X", probe->bRateControlMode);
-  printf("\nTemporal scale mode : %X", probe->bTemporalScaleMode);
-  printf("\nSpatial scale mode : %X", probe->bSpatialScaleMode);
-  printf("\nSNR scale mode : %X", probe->bSNRScaleMode);
-  printf("\nStream mux option : %X", probe->bStreamMuxOption);
-  printf("\nStream Format : %X", probe->bStreamFormat);
-  printf("\nEntropy CABAC : %X", probe->bEntropyCABAC);
-  printf("\nTimestamp : %X", probe->bTimestamp);
-  printf("\nNum of reorder frames : %d", probe->bNumOfReorderFrames);
-  printf("\nPreview flipped : %X", probe->bPreviewFlipped);
-  printf("\nView : %d", probe->bView);
-  printf("\nStream ID : %X", probe->bStreamID);
-  printf("\nSpatial layer ratio : %f", ((probe->bSpatialLayerRatio & 0xF0) >> 4) + ((float) (probe->bSpatialLayerRatio & 0x0F)) / 16);
-  printf("\nLeaky bucket size : %d ms\n", probe->wLeakyBucketSize);
-}
-
 static int device_open(AVFormatContext *ctx, const char* device_path)
 {
     struct video_data *s = ctx->priv_data;
@@ -792,13 +765,21 @@ static int v4l2_set_parameters(AVFormatContext *ctx)
         av_log(ctx, AV_LOG_WARNING, "Time per frame unknown\n");
 
     /** try using uvcvideo params **/
-    if (ctx->video_codec_id == AV_CODEC_ID_H264) {
+    if (ctx->video_codec_id == AV_CODEC_ID_H264 &&
+        (s->initial_bitrate != UVC_BITRATE_DEFAULT || s->iframe_interval != UVC_IFPERIOD_DEFAULT)) {
       uvcx_video_config_probe_commit_t probe;
 
       // Fill the probe. 0 means parameter is not negotiated.
       memset(&probe, 0, sizeof(probe));
-      make_uvc_xu_query(s->fd, UVCX_VIDEO_CONFIG_PROBE, UVC_GET_DEF, (uint8_t *) &probe);
-      probe.wIFramePeriod = s->iframe_interval / 2;
+
+      if (s->iframe_interval != UVC_IFPERIOD_DEFAULT) {
+        probe.wIFramePeriod = s->iframe_interval / 2;
+      }
+
+      if (s->initial_bitrate != UVC_BITRATE_DEFAULT) {
+        probe.dwBitRate = s->initial_bitrate;
+      }
+
       // Hints describe which parameters should remain unchanged
       probe.bmHints = UVC_H264_BMHINTS_RESOLUTION | UVC_H264_BMHINTS_PROFILE |
       UVC_H264_BMHINTS_FRAME_INTERVAL;
@@ -808,7 +789,6 @@ static int v4l2_set_parameters(AVFormatContext *ctx)
 
       // Get an offer from device
       make_uvc_xu_query(s->fd, UVCX_VIDEO_CONFIG_PROBE, UVC_GET_CUR, (uint8_t *) &probe);
-      print_probe_commit(&probe);
 
       // Finish negotiation
       make_uvc_xu_query(s->fd, UVCX_VIDEO_CONFIG_COMMIT, UVC_SET_CUR, (uint8_t *) &probe);
@@ -1173,7 +1153,8 @@ static const AVOption options[] = {
     { "abs",          "use absolute timestamps (wall clock)",                     OFFSET(ts_mode),      AV_OPT_TYPE_CONST,  {.i64 = V4L_TS_ABS      }, 0, 2, DEC, "timestamps" },
     { "mono2abs",     "force conversion from monotonic to absolute timestamps",   OFFSET(ts_mode),      AV_OPT_TYPE_CONST,  {.i64 = V4L_TS_MONO2ABS }, 0, 2, DEC, "timestamps" },
     { "use_libv4l2",  "use libv4l2 (v4l-utils) conversion functions",             OFFSET(use_libv4l2),  AV_OPT_TYPE_BOOL,   {.i64 = 0}, 0, 1, DEC },
-    { "iframe_interval",  "(Logitech C920) set interval between I-frames for H264 encoding",   OFFSET(iframe_interval),  AV_OPT_TYPE_INT,   {.i64 = 10000}, 0, INT_MAX, DEC },
+    { "iframe_interval",  "(Logitech C920) set interval (in ms) between I-frames",   OFFSET(iframe_interval),  AV_OPT_TYPE_INT,   {.i64 = UVC_IFPERIOD_DEFAULT}, 0, INT_MAX, DEC },
+    { "bitrate",  "(Logitech C920) set bitrate for H264 encoding",   OFFSET(initial_bitrate),  AV_OPT_TYPE_INT,   {.i64 = UVC_BITRATE_DEFAULT}, 0, INT_MAX, DEC },
     { NULL },
 };