Nvv4l2h264enc failing on Jetpack 5.1 when called through gstreamer library's C API

[ian82]

My application uses the gstreamer C API to perform h.264 and h.265 encoding. This means we don’t use gstreamer-1.0, our C++ code includes the gstreamer library and calls gst_parse_launch to create the pipeline.

This works fine on Jetpack 4, and it works fine on Jetpack 5.1 with the h.265 encoder. However, when I try the h.264 encoder it fails to generate key frames. It generates only the first IDR frame, followed by an endless series of P frames. (I checked the NALU headers to confirm that no more IDR frames are being generated).

Our code is exactly the same on Jetpack 4 and Jetpack 5.1. This is the gstreamer pipeline:

appsrc name=vidframe ! videoconvert ! video/x-raw, width=1280, height=720, format=UYVY, framerate=15/1 ! nvvidconv ! nvv4l2h264enc insert-aud=1 insert-sps-pps=1 control-rate=1 bitrate=1800000 peak-bitrate=3600000 vbv-size=5000000 profile=4 preset_level=4 name=videnc ! h264parse ! appsink name=appsink sync=false

I tried to use the “force IDR” API to work around the problem, but no luck. I am not sure I am using “force IDR” correctly, I’m trying to use the following code:

GstStructure* structure = gst_structure_new_empty(“force-idr”);
GstEvent* event = gst_event_new_custom(GST_EVENT_CUSTOM_DOWNSTREAM, structure);
gst_element_send_event(p_impl->gstreamer_encoder_, event);

[Honey_Patouceul]

You may try setting nvv4l2h264enc property idrinterval:

... ! nvv4l2h264enc idrinterval=30 ...

[ian82]

That works! Thank you for the very fast and very accurate suggestion.

Looks like jetpack 4 always sets IDR interval to 30 frames, and in jetpack 5 there is a new API “idrinterval” to specify it yourself. Maybe the default was changed to something much higher than 30 frames…

[Honey_Patouceul]

Seems default is 256 for my L4T release R35.1 with gstreamer 1.16.3:

gst-inspect-1.0 nvv4l2h264enc
...
 idrinterval         : Encoding IDR Frame occurance frequency
                        flags: readable, writable, changeable only in NULL or READY state
                        Unsigned Integer. Range: 0 - 4294967295 Default: 256