Presentation for RustTechX 2024

https://rusttechx.com/

rusttechx-2024/Makefile

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+all:
+	make slide slideshow
+
+slide:
+	pandoc -t beamer rusttechx.md --filter pandoc-plot -f markdown-implicit_figures -V colorlinks=true -V linkcolor=blue -V urlcolor=red -o rusttechx-2024.pdf
+
+slideshow:
+	pandoc -t beamer rusttechx.md --filter pandoc-plot -f markdown-implicit_figures -i -V colorlinks=true -V linkcolor=blue -V urlcolor=red -o rusttechx-2024-slideshow.pdf
+
+view:
+	zathura --mode=presentation rusttechx-2024.pdf &

rusttechx-2024/rusttechx.md

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+---
+title:
+- Multimedia using Rust and GStreamer
+author:
+- Sanchayan Maity
+theme:
+- default
+classoption:
+- aspectratio=169
+---
+
+# Who?
+
+- Consultant Software Engineer @ [asymptotic](https://asymptotic.io/)
+    - Open source consulting firm based out of Toronto, Bangalore & Hyderabad
+    - Work on low level systems software centred around multimedia
+    - GStreamer, PipeWire, PulseAudio
+- Embedded Systems background
+- C, Rust and Haskell
+- Organizing Rust and Haskell meetup Bangalore since 2018
+
+# Agenda
+
+- Introduction to GStreamer
+- Why Rust
+- Rust and GStreamer
+
+# GStreamer
+
+- Multiplatform Pipeline based multimedia framework
+- Bindings for various languages
+- Supported on Linux, macOS, Android and Windows
+- Allows building complex media processing workflows
+- Some applications
+  * GstLAL (gravitational wave data analysis)
+  * PiTiVi (Video Editor)
+  * amaroK, Banshee, Clementine (audio players)
+  * Empathy (VOIP and video conferencing)
+  * Rygel (DLNA streaming server and renderer)
+  * Showtime, Clapper, Totem (Media players for desktop)
+
+# Simple pipeline
+
+  ```bash
+  gst-launch-1.0 videotestsrc ! autovideosink
+  gst-launch-1.0 audiotestsrc ! autoaudiosink
+  ```
+
+# Media pipeline[^1]
+
+![*_Simple Player_*](simple-player.png){width=80%}
+
+[^1]: [Dynamic Pipelines](https://gstreamer.freedesktop.org/documentation/tutorials/basic/dynamic-pipelines.html?gi-language=c)
+
+# Playback pipeline
+
+```bash
+gst-play-1.0 https://devstreaming-cdn.apple.com/videos/streaming/examples/\n
+img_bipbop_adv_example_ts/master.m3u8
+```
+
+# Playback pipeline graph
+
+![*_playbin HLS_*](playbin-hls.svg)
+
+# Custom elements
+
+![*_Rounded Corners_*](roundedcorners.jpg){width=60%}
+
+```bash
+gst-launch-1.0 filesrc location=bunny.mp4 ! decodebin ! videoconvert !
+roundedcorners border-radius-px=100 ! videoconvert ! gtksink
+```
+
+# Why Rust?
+
+- Codec implementations in pure Rust (Rust Audio, Xiph AV1, Symphonia)
+- Things we care about
+  * **Low cognitive overhead**
+  * Immutability
+  * Expressive type system
+  * Memory safety and concurrency
+  * Foreign Function Interface
+
+# Why Rust?
+
+- Bindings/abstractions over GLib/GObject[^2]
+- Provides a root for the object hierarchy tree filed in by the GStreamer library
+- Gives basic reference counting, parenting functionality and locking.
+- GObject
+    - GstObject
+        - GstAllocator
+        - GstBufferPool
+        - GstBus
+        - GstClock
+        - GstDevice
+        - GstDeviceMonitor
+        - GstDeviceProvider
+        - GstElement
+        - GstPad
+        - ...
+- GStreamer bindings
+
+[^2]: [GstObject](https://gstreamer.freedesktop.org/documentation/gstreamer/gstobject.html?gi-language=c)
+
+# Why immutability and types matter?
+
+```c
+      let caps: gst::Caps = gst::Caps::builder("video/x-raw")
+          .field("width", crop_w)
+          .field("height", crop_h)
+          .field("pixel-aspect-ratio", gst::Fraction::new(1, 1))
+          .build();
+      let s = caps.remove_structure(0);
+```
+
+# Why immutability and types matter?
+
+```bash
+warning: unused variable: `s`
+   --> video-bin/src/imp.rs:152:13
+    |
+152 |         let s = caps.remove_structure(0);
+    |             ^ help: if this is intentional, prefix it with an
+                    underscore: `_s`
+    |
+    = note: `#[warn(unused_variables)]` on by default
+error[E0596]: cannot borrow data in dereference of `gstreamer::Caps`
+              as mutable
+   --> video-bin/src/imp.rs:152:17
+    |
+152 |         let s = caps.remove_structure(0);
+    |                 ^^^^^^^^^^^^^^^^^^^^^^^^ cannot borrow as mutable
+    |
+    = help: trait `DerefMut` is required to modify through a dereference,
+            but it is not implemented for `gstreamer::Caps`
+```
+
+# Why immutability and types matter?
+
+```c
+        let mut caps: gst::Caps = gst::Caps::builder("video/x-raw")
+            .field("width", crop_w)
+            .field("height", crop_h)
+            .field("pixel-aspect-ratio", gst::Fraction::new(1, 1))
+            .build();
+        let _s = caps.remove_structure(0);
+```
+
+
+# Why immutability and types matter?
+
+```bash
+warning: variable does not need to be mutable
+   --> video-bin/src/imp.rs:147:13
+    |
+147 |         let mut caps: gst::Caps = gst::Caps::builder("video/x-raw")
+    |             ----^^^^
+    |             |
+    |             help: remove this `mut`
+    |
+    = note: `#[warn(unused_mut)]` on by default
+error[E0596]: cannot borrow data in dereference of `gstreamer::Caps`
+              as mutable
+   --> video-bin/src/imp.rs:152:18
+    |
+152 |         let _s = caps.remove_structure(0);
+    |                  ^^^^^^^^^^^^^^^^^^^^^^^^ cannot borrow as mutable
+    = help: trait `DerefMut` is required to modify through a dereference,
+            but it is not implemented for `gstreamer::Caps`
+```
+
+# Why immutability and types matter?
+
+```c
+        let caps: gst::Caps = gst::Caps::builder("video/x-raw")
+            .field("width", crop_w)
+            .field("height", crop_h)
+            .field("pixel-aspect-ratio", gst::Fraction::new(1, 1))
+            .build();
+        let caps = caps.get_mut().unwrap();
+        let _s = caps.remove_structure(0);
+```
+
+# Why immutability and types matter?
+
+```bash
+error[E0596]: cannot borrow `caps` as mutable, as it is not declared
+              as mutable
+   --> video-bin/src/imp.rs:152:20
+    |
+147 |         let caps: gst::Caps = gst::Caps::builder("video/x-raw")
+    |             ---- help: consider changing this to be mutable:
+                      `mut caps`
+...
+152 |         let caps = caps.get_mut().unwrap();
+    |                    ^^^^^^^^^^^^^^ cannot borrow as mutable
+
+For more information about this error, try `rustc --explain E0596`.
+```
+
+# Why immutability and types matter?
+
+```c
+        let mut caps: gst::Caps = gst::Caps::builder("video/x-raw")
+            .field("width", crop_w)
+            .field("height", crop_h)
+            .field("pixel-aspect-ratio", gst::Fraction::new(1, 1))
+            .build();
+        if let Some(caps) = caps.get_mut() {
+            let _s = caps.remove_structure(0);
+        }
+```
+
+# GStreamer & Rust
+
+- Some stats[^3]
+    - gstreamer-rs: ~2700 commits, gst-plugins-rs: ~2600 commits
+    - gstreamer-rs: ~85 contributors, gst-plugins-rs: ~110 contributors
+    - gst-plugins-rs: ~ +180k SLOC / -37k SLOC
+    - gst-plugins-rs: Overall 47 plugins, 149 elements
+- In relation to the GStreamer monorepo
+    - 1.22 cycle: ~33% commits / MRs in Rust modules
+    - 1.24 cycle: ~25% commits / MRs in Rust modules
+
+[^3]: [GStreamer & Rust: What has happened over the last 5 years](https://gstconf.ubicast.tv/videos/gstreamer-rust-what-has-happened-over-the-last-5-years_f8qxhpuzi9/)
+
+# Resources
+
+- [GObject subclassing in Rust ](https://www.youtube.com/watch?v=TSf3rVyv7c8)
+- [GStreamer bindings for Rust](https://gitlab.freedesktop.org/gstreamer/gstreamer-rs)
+- [Rust GStreamer Plugins](https://gitlab.freedesktop.org/gstreamer/gst-plugins-rs)
+- [Using GStreamer](https://www.youtube.com/watch?v=ZphadMGufY8)
+- [How to get started with GStreamer](https://www.youtube.com/watch?v=OkOsm9FyzdM&t=2s)
+- [GStreamer for your backend services](https://asymptotic.io/blog/gstreamer-for-your-backend-services/)
+
+# Questions?
+
+- Rust Bangalore
+  * Meetup: https://hasgeek.com/rustbangalore
+  * Telegram: t.me/RustIndia
+- Reach out on
+  * email:
+
+        - me@sanchayanmaity.net
+        - sanchayan@asymptotic.io
+        - hello@asymptotic.io
+  * Mastodon: [sanchayanmaity.com](https://sanchayanmaity.com/@sanchayan)
+  * Blog: [sanchayanmaity.net](https://sanchayanmaity.net/)