presentations/rust-bangalore-april-2024/hls.md

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---
title:
- HTTP Live Streaming (HLS)
author:
- Sanchayan Maity
theme:
- default
classoption:
- aspectratio=169
---
# Who
- Who am I?
* Embedded Systems background
* Prefer C, Haskell and Rust
* Organize and speak at Rust and Haskell meet-ups in Bangalore
- Work?
* Software Engineer @ [asymptotic](https://asymptotic.io/)
* Open source consulting firm based out of Bangalore and Toronto
* Work on low level systems software centred around multimedia
* GStreamer, PipeWire, PulseAudio
* Language Polyglots
# Open source contributions
- [GStreamer](https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests?scope=all&state=all&author_username=SanchayanMaity)
- [gst-plugins-rs](https://gitlab.freedesktop.org/gstreamer/gst-plugins-rs/-/merge_requests?scope=all&state=all&author_username=SanchayanMaity)
- [PipeWire](https://gitlab.freedesktop.org/pipewire/pipewire/-/merge_requests?scope=all&state=all&author_username=SanchayanMaity)
- [PulseAudio](https://gitlab.freedesktop.org/pulseaudio/pulseaudio/-/merge_requests?scope=all&state=all&author_username=SanchayanMaity)
- [Linux](https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/log/?qt=author&q=Sanchayan+Maity)
- [u-boot](https://source.denx.de/u-boot/u-boot/-/commits/master?search=Sanchayan%20Maity)
# Agenda
- Whirlwind tour of GStreamer
- What's HTTP Live Streaming (HLS)
- HLS implementation
# GStreamer
- Multiplatform Pipeline based multimedia framework
- Bindings for various languages
- Allows building complex media processing workflows
- Some applications
* PiTiVi (Video Editor)
* amaroK, Banshee, Clementine (audio players)
* Empathy (VOIP and video conferencing)
* GstLAL (gravitational wave data analysis)
* Rygel (DLNA streaming server and renderer)
* Totem (movie player for the GNOME 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)
# HLS
- HTTP-based adaptive bit-rate streaming communications protocol
- Developed by Apple and released in 2009
- Standardised in [RFC 8216](https://datatracker.ietf.org/doc/html/rfc8216)
- HTTP traffic, unlike UDP-based protocols such as RTP
- Content can be offered from conventional HTTP servers
- Delivered over widely available HTTP-based content delivery networks
# Motivation
- Video on demand content
* HLS is better than just serving media directly over HTTP
* Can describe metadata
* Variants using a bit rate ladder
- Alternate media renditions
- Live content
* Reuse the same mechanism
* Trading off lower cost distribution via CDN at the cost of latency over real time
# Playlist[^2]
```m3u8
#EXTM3U
#EXT-X-TARGETDURATION:10
#EXT-X-VERSION:3
#EXTINF:9.009,
http://media.example.com/first.ts
#EXTINF:9.009,
http://media.example.com/second.ts
#EXTINF:3.003,
http://media.example.com/third.ts
#EXT-X-ENDLIST
```
[^2]: [RFC 8216](https://datatracker.ietf.org/doc/html/rfc8216#page-50)
# Master playlist[^3]
```m3u8
#EXTM3U
#EXT-X-STREAM-INF:BANDWIDTH=1280000,AVERAGE-BANDWIDTH=1000000
http://example.com/low.m3u8
#EXT-X-STREAM-INF:BANDWIDTH=2560000,AVERAGE-BANDWIDTH=2000000
http://example.com/mid.m3u8
#EXT-X-STREAM-INF:BANDWIDTH=7680000,AVERAGE-BANDWIDTH=6000000
http://example.com/hi.m3u8
#EXT-X-STREAM-INF:BANDWIDTH=65000,CODECS="mp4a.40.5"
http://example.com/audio-only.m3u8
```
[^3]: [RFC 8216](https://datatracker.ietf.org/doc/html/rfc8216#section-8.4)
# Master playlist[^4]
```m3u8
#EXTM3U
#EXT-X-MEDIA:TYPE=AUDIO,GROUP-ID="aac",NAME="English", \
DEFAULT=YES,AUTOSELECT=YES,LANGUAGE="en", \
URI="main/english-audio.m3u8"
#EXT-X-MEDIA:TYPE=AUDIO,GROUP-ID="aac",NAME="Deutsch", \
DEFAULT=NO,AUTOSELECT=YES,LANGUAGE="de", \
URI="main/german-audio.m3u8"
#EXT-X-STREAM-INF:BANDWIDTH=1280000,CODECS="...",AUDIO="aac"
low/video-only.m3u8
#EXT-X-STREAM-INF:BANDWIDTH=2560000,CODECS="...",AUDIO="aac"
mid/video-only.m3u8
#EXT-X-STREAM-INF:BANDWIDTH=7680000,CODECS="...",AUDIO="aac"
hi/video-only.m3u8
#EXT-X-STREAM-INF:BANDWIDTH=65000,CODECS="mp4a.40.5",AUDIO="aac"
main/english-audio.m3u8
```
[^4]: [RFC 8216](https://datatracker.ietf.org/doc/html/rfc8216#section-8.6)
# Implementation
- New GStreamer plugin
- Written in Rust
- Uses [m3u8-rs](https://docs.rs/m3u8-rs/latest/m3u8_rs/) and existing [`hlssink3`](https://gitlab.freedesktop.org/gstreamer/gst-plugins-rs/-/tree/main/net/hlssink3?ref_type=heads)
- Open MR: https://gitlab.freedesktop.org/gstreamer/gst-plugins-rs/-/merge_requests/1515
# Demo
Using
- [videojs](https://videojs.com/)
- `python3 -m http.server`
- Sample GStreamer Rust Code[^5]
[^5]: [HLS sample app](https://git.sanchayanmaity.net/sanchayanmaity/gst-hlssink4)
# References
- [RFC 8216](https://datatracker.ietf.org/doc/html/rfc8216)
- [HLS in depth](https://dyte.io/blog/hls-in-depth/)
- [LL-HLS in depth](https://dyte.io/blog/ll-hls-in-depth/)
- [HTTP Live Streaming - A Practical Guide](https://hlsbook.net/)
- [HTTP Live Streaming - Wikipedia](https://en.wikipedia.org/wiki/HTTP_Live_Streaming)
# Questions
- Reach out on
* Email: sanchayan@sanchayanmaity.net
* Mastodon: [sanchayanmaity.com](https://sanchayanmaity.com/@sanchayan)
* Telegram: https://t.me/SanchayanMaity
* Blog: [sanchayanmaity.net](https://sanchayanmaity.net/)