Add very basic support for video thumbnails

Signed-off-by: trivernis <trivernis@protonmail.com>

Cargo.toml

@@ -4,16 +4,18 @@ readme = "README.md"
 license = "Apache-2.0"
 authors = ["trivernis <trivernis@protonmail.com>"]
 description = "An image thumbnail creation library"
-version = "0.2.0"
+version = "0.2.1"
 edition = "2018"
+repository = "https://github.com/Trivernis/thumbnailer"
 
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
 webp = "0.2.0"
 mime = "0.3.16"
-thiserror = "1.0.30"
 rayon = "1.5.1"
+vid2img = "0.1.0"
+tempfile = "3.2.0"
 
 [dependencies.image]
 version = "0.23.14"

src/error.rs

@@ -1,20 +1,76 @@
-use std::io;
+use image::ImageError;
 use mime::Mime;
-use thiserror::Error;
+use std::fmt::{Debug, Display, Formatter};
+use std::io;
+use vid2img::{CaptureError, StreamError};
 
 pub type ThumbResult<T> = Result<T, ThumbError>;
 
-#[derive(Debug, Error)]
+#[derive(Debug)]
 pub enum ThumbError {
-    #[error("IO Error {0}")]
-    IO(#[from] io::Error),
+    IO(io::Error),
 
-    #[error("Image Error {0}")]
-    Image(#[from] image::error::ImageError),
+    Image(image::error::ImageError),
 
-    #[error("Failed to decode image")]
     Decode,
 
-    #[error("Unsupported media type {0}")]
     Unsupported(Mime),
-}
+
+    NullVideo,
+
+    CaptureError(vid2img::CaptureError),
+
+    StreamError(vid2img::StreamError),
+}
+
+impl Display for ThumbError {
+    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
+        match self {
+            ThumbError::IO(_) => write!(f, "an io error occurred"),
+            ThumbError::Image(e) => write!(f, "an image error occurred {}", e),
+            ThumbError::Decode => write!(f, "failed to decode image"),
+            ThumbError::Unsupported(mime) => write!(f, "Unsupported media type {}", mime),
+            ThumbError::NullVideo => write!(f, "no video data found in file"),
+            ThumbError::CaptureError(c) => {
+                write!(f, "capture error when creating video thumbnail: {:?}", c)
+            }
+            ThumbError::StreamError(s) => {
+                write!(f, "stream error when creating video thumbnail: {:?}", s)
+            }
+        }
+    }
+}
+
+impl std::error::Error for ThumbError {
+    fn source(&self) -> Option<&(dyn std::error::Error + 'static)> {
+        match self {
+            ThumbError::IO(e) => e.source(),
+            ThumbError::Image(i) => i.source(),
+            _ => None,
+        }
+    }
+}
+
+impl From<io::Error> for ThumbError {
+    fn from(e: io::Error) -> Self {
+        Self::IO(e)
+    }
+}
+
+impl From<image::error::ImageError> for ThumbError {
+    fn from(e: ImageError) -> Self {
+        Self::Image(e)
+    }
+}
+
+impl From<vid2img::CaptureError> for ThumbError {
+    fn from(e: CaptureError) -> Self {
+        Self::CaptureError(e)
+    }
+}
+
+impl From<vid2img::StreamError> for ThumbError {
+    fn from(s: StreamError) -> Self {
+        Self::StreamError(s)
+    }
+}

src/formats/mod.rs

@@ -1,15 +1,18 @@
 use crate::error::{ThumbError, ThumbResult};
 use crate::formats::image_format::read_image;
+use crate::formats::video_format::get_video_frame;
 use image::DynamicImage;
 use mime::Mime;
 use std::io::{BufRead, Seek};
 
 pub mod image_format;
+pub mod video_format;
 
 /// Reads the buffer content into an image that can be used for thumbnail generation
 pub fn get_base_image<R: BufRead + Seek>(reader: R, mime: Mime) -> ThumbResult<DynamicImage> {
     match mime.type_() {
         mime::IMAGE => read_image(reader, mime),
+        mime::VIDEO => get_video_frame(reader, mime),
         _ => Err(ThumbError::Unsupported(mime)),
     }
 }

src/formats/video_format.rs

@@ -0,0 +1,37 @@
+use crate::error::{ThumbError, ThumbResult};
+use image::png::PngDecoder;
+use image::DynamicImage;
+use mime::Mime;
+use std::fs;
+use std::io::{BufRead, Seek};
+use std::path::PathBuf;
+use vid2img::FileSource;
+
+pub fn get_video_frame<R: BufRead + Seek>(mut reader: R, mime: Mime) -> ThumbResult<DynamicImage> {
+    let tempdir = tempfile::tempdir()?;
+    tempdir.path();
+    let path = PathBuf::from(tempdir.path())
+        .join("video")
+        .with_extension(mime.subtype().as_str());
+
+    let mut buf = Vec::new();
+    reader.read_to_end(&mut buf)?;
+    fs::write(&path, buf)?;
+
+    let img = extract_frame_from_video(&path)?;
+    tempdir.close()?;
+
+    Ok(img)
+}
+
+fn extract_frame_from_video(path: &PathBuf) -> ThumbResult<DynamicImage> {
+    let source = FileSource::new(path, (2000, 2000))?;
+    for frame in source.into_iter() {
+        if let Ok(Some(data)) = frame {
+            let decoder = PngDecoder::new(data.as_slice())?;
+            let img = DynamicImage::from_decoder(decoder)?;
+            return Ok(img);
+        }
+    }
+    Err(ThumbError::NullVideo)
+}

tests/video_reading.rs

@@ -0,0 +1,21 @@
+use mime::Mime;
+use std::io::Cursor;
+use std::str::FromStr;
+use thumbnailer::{create_thumbnails, ThumbnailSize};
+
+const VIDEO_BYTES: &'static [u8] = include_bytes!("assets/test.mp4");
+
+#[test]
+fn it_creates_thumbnails_for_mp4() {
+    let reader = Cursor::new(VIDEO_BYTES);
+    create_thumbnails(
+        reader,
+        Mime::from_str("video/mp4").unwrap(),
+        [
+            ThumbnailSize::Small,
+            ThumbnailSize::Medium,
+            ThumbnailSize::Large,
+        ],
+    )
+    .unwrap();
+}