# voxl-streamer decimator

Source: https://forum.modalai.com/topic/935/voxl-streamer-decimator
Category: General Questions (https://forum.modalai.com/category/2/general-questions)
Posted: 2022-05-13 11:19:12 UTC by Philemon Benner
Replies: 4 · Views: 925

## Philemon Benner · 2022-05-13 11:19:12 UTC

Hey,
i'm currently pushing frames from tflite-server to voxl-streamer rtsp. My question is what the decimator parameter in /etc/modalai/voxl-streamer.conf exactly does, because when you lower it fps are higher resolution goes down, if i set a higher value fps are less but image quality gets better.

In https://gitlab.com/voxl-public/voxl-sdk/utilities/voxl-streamer/-/blob/master/src/main.c
```
ctx->input_frame_rate /= ctx->output_frame_decimator;
ctx->output_frame_rate = ctx->input_frame_rate;
```
it seems to just cut down the input frame rate. But why does the resolution change if we just lower the output_frame_rate ?

## Reply by Philemon Benner · 2022-05-13 14:32:57 UTC

also besides that would be nice if you add
```
voxl-configure-pkg-manager
```
to the docs

## Reply by Eric Katzfey (ModalAI staff) · 2022-05-13 15:21:43 UTC

@Philemon-Benner When you say resolution goes down are you referring to image quality or the actual width x height resolution? If you are talking about image quality that makes sense because the video encoder is working toward a target output bit rate. If you have more frames in one second then it has to decrease quality in order to meet the target output bit rate.

## Reply by Philemon Benner · 2022-05-13 15:46:46 UTC

@Eric-Katzfey it's the image quality. Thanks for the fast answer ☺️

## Reply by Eric Katzfey (ModalAI staff) · 2022-05-13 15:51:23 UTC (in reply to Philemon Benner)

@Philemon-Benner No problem. But that's exactly why the decimator is there. It's often nicer to see lower frame rate with higher image quality.