diff --git a/examples/multiplane.rs b/examples/multiplane.rs
index 139a541..1b724db 100644
--- a/examples/multiplane.rs
+++ b/examples/multiplane.rs
@@ -2,10 +2,12 @@ use std::env;
 use std::path::PathBuf;
 use vivotk::codec::decoder::Tmc2rsDecoder;
 use vivotk::codec::Decoder;
-use vivotk::pcd::PointCloudData;
+use vivotk::pcd::{write_pcd_file, PCDDataType, PointCloudData};
 
 fn main() {
-    let _output_file = env::args().nth(1).expect("output file");
+    let output_folder = env::args()
+        .nth(1)
+        .expect("output folder (e.g. . or ./data)");
     let left = env::args().nth(2).expect("input file");
     let bottom = env::args().nth(3).expect("input file");
     let back = env::args().nth(4).expect("input file");
@@ -23,10 +25,13 @@ fn main() {
     ]);
     let now = std::time::Instant::now();
     decoder.start().unwrap();
+    let mut file_counter = 1;
     while let Some(pc) = decoder.poll() {
         let pcd = PointCloudData::from(&pc);
         dbg!(pcd.header().points());
-        // write_pcd_file(&pcd, PCDDataType::Ascii, &output_file).unwrap();
+        let filename = format!("{}/{}.pcd", output_folder, file_counter);
+        file_counter += 1;
+        write_pcd_file(&pcd, PCDDataType::Ascii, &filename).unwrap();
     }
     let elapsed = now.elapsed();
     dbg!("Decoding took {:?} seconds", elapsed);
diff --git a/shell.nix b/shell.nix
index f80375f..b406055 100644
--- a/shell.nix
+++ b/shell.nix
@@ -2,9 +2,13 @@ with (import <nixpkgs> {});
 stdenv.mkDerivation {
   name = "rust-env";
   buildInputs = [
-    ffmpeg
+    ffmpeg_4
     libiconvReal
     pkg-config
+    pkgs.darwin.apple_sdk.frameworks.Security
+    pkgs.darwin.apple_sdk.frameworks.ApplicationServices
+    pkgs.darwin.apple_sdk.frameworks.CoreVideo
+    pkgs.darwin.apple_sdk.frameworks.AppKit
   ];
 
   # Set Environment variables
diff --git a/src/bin/exporter.rs b/src/bin/exporter.rs
index 6413bf2..f553d93 100644
--- a/src/bin/exporter.rs
+++ b/src/bin/exporter.rs
@@ -144,7 +144,7 @@ async fn main() {
                 let pc = decoder.poll().unwrap();
                 png_writer.write_to_png(&pc, &(i + frame_number as usize).to_string());
             }
-            frame_number += 30;
+            frame_number += args.segment_size as u64;
         }
     } else if let Some(ply_folder) = args.ply_folder {
         let mut ply_files: Vec<PathBuf> = vec![];