Compute blurhash

src/processing/blurhash.rs

@@ -0,0 +1,42 @@
+use std::{ptr, slice};
+use std::intrinsics::transmute;
+use std::time::SystemTime;
+
+use anyhow::Error;
+use blurhash::encode;
+use ffmpeg_sys_the_third::{av_frame_alloc, av_frame_free, AVFrame, sws_freeContext, sws_getContext, sws_scale_frame};
+use ffmpeg_sys_the_third::AVPixelFormat::AV_PIX_FMT_RGBA;
+use log::info;
+
+pub unsafe fn make_blur_hash(frame: *mut AVFrame, detail: u32) -> Result<String, Error> {
+    let start = SystemTime::now();
+    let sws_ctx = sws_getContext((*frame).width,
+                                 (*frame).height,
+                                 transmute((*frame).format),
+                                 (*frame).width,
+                                 (*frame).height,
+                                 AV_PIX_FMT_RGBA,
+                                 0, ptr::null_mut(), ptr::null_mut(), ptr::null_mut());
+    if sws_ctx.is_null() {
+        return Err(Error::msg("Failed to create sws context"));
+    }
+
+    let mut dst_frame = av_frame_alloc();
+    let ret = sws_scale_frame(sws_ctx, dst_frame, frame);
+    if ret < 0 {
+        return Err(Error::msg("Failed to scale frame (blurhash)"));
+    }
+
+    let pic_slice = slice::from_raw_parts_mut((*dst_frame).data[0], ((*frame).width * (*frame).height * 4) as usize);
+    let bh = encode(detail, detail,
+                    (*frame).width as u32,
+                    (*frame).height as u32,
+                    pic_slice,
+    )?;
+
+    av_frame_free(&mut dst_frame);
+    sws_freeContext(sws_ctx);
+
+    info!("Generated blurhash in {}ms", SystemTime::now().duration_since(start).unwrap().as_millis());
+    Ok(bh)
+}