I wonder whether we should expose additional CLI parameters / UI controls for this.

I believe this is already configurable via the enc-opts

-x scenario=<default | display_remoting | video_conference | archive | live_streaming | camera_record display_remoting_with_feature_map>

https://github.com/FFmpeg/FFmpeg/blob/08b1bffa49715a9615acc025dfbea252d8409e1f/libavcodec/mfenc.c#L1289

Note the block further up in this file:

            job->vcodec == HB_VCODEC_FFMPEG_MF_H265 ||
            job->vcodec == HB_VCODEC_FFMPEG_MF_AV1) {
            av_dict_set(&av_opts, "rate_control", "u_vbr", 0); // options are cbr, pc_vbr, u_vbr, ld_vbr, g_vbr, gld_vbr

            // On Qualcomm encoders, the VBR modes can easily drop frames if
            // the rate control feels like it needs it (in certain
            // configurations), unless scenario is set to camera_record.
            av_dict_set(&av_opts, "scenario", "camera_record", 0);
        }

https://github.com/HandBrake/HandBrake/blob/a9f1ad7749ac4624fa2c515472377b13d16f6cd0/libhb/encavcodec.c#L457C58-L457C59

Is this no longer the case? If so, we should remove that block of code at the same time.

@sr55 I've noticed this comment. I'm checking on this. I'll get back as soon as I have confirmed this.

@sr55 The encoder has a free hand in dropping a frame when it runs on vbr mode. With the recent upgrades in the HW and drivers, the encoder shall not drop frames unnecessarily, but still it is recommended to set AVScenario to camera-record when running on vbr mode.

I did try to comment out L457 and run a couple of encodes with different bitrate values and didn't observe any frame drops.

@sr55 Any update on this?