From 61250ffaa2d6a91fcbdc91ecd741a7821b69b87c Mon Sep 17 00:00:00 2001
From: Luna <git@l4.pm>
Date: Sun, 11 Jun 2023 23:00:12 -0300
Subject: [PATCH] use faster seeking in ffmpeg

---
 src/main.rs | 38 +++++++++++++++++++++++---------------
 1 file changed, 23 insertions(+), 15 deletions(-)

diff --git a/src/main.rs b/src/main.rs
index a9384a3..64b0ad9 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -171,18 +171,21 @@ async fn fetch_frame_as_image(
     input_path: &str,
     output_path: &str,
     frame_index: usize,
+    frame_rate: f64, // X/1sec
 ) -> anyhow::Result<()> {
     let frame_index_param = format!("select=eq(n\\,{})", frame_index);
+    let timeline_index: f64 = frame_index as f64 / frame_rate;
+    let timeline_index_param = format!("{:.5}", timeline_index);
     let builder = ffmpeg_cli::FfmpegBuilder::new()
         .stderr(Stdio::piped())
         .option(Parameter::Single("nostdin"))
         .option(Parameter::Single("y"))
-        .input(ffmpeg_cli::File::new(input_path))
-        .output(
-            ffmpeg_cli::File::new(output_path)
-                .option(Parameter::KeyValue("vf", &frame_index_param))
-                .option(Parameter::KeyValue("vframes", "1")),
-        );
+        // fast seeking with -ss instead of select filter
+        .input(
+            ffmpeg_cli::File::new(input_path)
+                .option(Parameter::KeyValue("ss", &timeline_index_param)),
+        )
+        .output(ffmpeg_cli::File::new(output_path).option(Parameter::KeyValue("vframes", "1")));
 
     log::debug!("running {:?}", builder);
     let ffmpeg = builder.run().await.unwrap();
@@ -259,36 +262,41 @@ async fn upload_file(
             let frame_rate_str = stream.r_frame_rate.clone();
 
             let parts = frame_rate_str.split("/").into_iter().collect::<Vec<_>>();
-            let frame_rate =
-                parts.get(0).unwrap().parse::<u32>()? / parts.get(1).unwrap().parse::<u32>()?;
+            let frame_rate: f64 =
+                parts.get(0).unwrap().parse::<f64>()? / parts.get(1).unwrap().parse::<f64>()?;
 
-            let total_length_in_seconds = total_frame_count / frame_rate;
-            let wanted_frame_skip_seconds = match total_length_in_seconds {
+            let total_length_in_seconds = total_frame_count as f64 / frame_rate;
+            let wanted_frame_skip_seconds = match total_length_in_seconds as usize {
                 0..=10 => 2,
                 11..=60 => 10,
                 61..=120 => 15,
-                121.. => 20,
-            };
-            let wanted_frame_skip = (wanted_frame_skip_seconds * frame_rate).try_into().unwrap();
+                121..=300 => 20,
+                301.. => 30,
+                _ => 33,
+            } as f64;
+            let wanted_frame_skip = wanted_frame_skip_seconds * frame_rate;
 
             let temporary_frame_dir = tempfile::tempdir()?;
             let temporary_frame_path =
                 format!("{}/frame.png", temporary_frame_dir.path().to_string_lossy());
-            log::info!("path: '{}'", &temporary_frame_path);
+            log::info!("frame path: '{}'", &temporary_frame_path);
             log::info!("wanted_frame_skip: {}", &wanted_frame_skip_seconds);
 
-            for frame_number in (0..total_frame_count).step_by(wanted_frame_skip) {
+            for frame_number in (0..total_frame_count).step_by(wanted_frame_skip as usize) {
                 log::info!("extracting frame {:?}", frame_number);
                 fetch_frame_as_image(
                     temp_file.path().to_str().unwrap(),
                     &temporary_frame_path,
                     frame_number.try_into().unwrap(),
+                    frame_rate,
                 )
                 .await?;
+                log::info!("extracted frame {:?}", frame_number);
 
                 let mut actual_frame_file = std::fs::File::open(&temporary_frame_path)?;
                 let mut frame_data = vec![];
                 actual_frame_file.read_to_end(&mut frame_data)?;
+                log::info!("sending frame {:?}", frame_number);
                 let tags_from_frame = if let WrappedResponse::Tags(tags_from_frame) =
                     send_image_to_dd(frame_data, "amongus.png".to_string(), "image/png", &options)
                         .await?