SF Video Tech meetup: Frame Accurate Video Playback In The Browser

Abstract Livestreaming could be quite challenging, but it is possible to create a simple proof of concept of live streaming platform in few lines of code, here I show you how to do that VOD demo Live demo

Super fast HLS trimming with frame accuracy

Description This article is an evolution of this code: Trim HLS stream with frame accuracy using ffmpeg and Bash script The implementation gets a group if HLS chunks (.ts) and based on input and output points (timestamps) it creates an mp4 output file frame accuracy trimmed, and with AV perfectly aligned. Thanks to the underlying algorithmContinue reading “Super fast HLS trimming with frame accuracy”

A minimal h264 “encoder” (C++)

Introduction I always thought that the best approach to complex things is to start from the basis, and once you control this part enter step by step towards more complex parts. With this idea in mind and the aim to improve my understanding of h264 bitstream and its techniques I have created the following code in C++ that generates a compliant h264 file fromContinue reading “A minimal h264 “encoder” (C++)”

The audio video alignment nightmare in audio compressed formats

Introduction Doing some research about automatic editing systems I have found strange timing behaviors in audio compressed streams and I wanted to take some measures, and here they are: Audio tests – Audacity Using Audacity  2.0.5 (free audio editor) I generated a test time line, see figure 1 After that I have exported the test timelineContinue reading “The audio video alignment nightmare in audio compressed formats”

Trim HLS stream with frame accuracy using ffmpeg and Bash script

Introduction The main idea of this post is to practise with ffmpeg and write down my experiences, issues that I have found, possible solutions, etc. To achieve that I developed a group of bash scripts that are able to trim a HLS stream using ffmpeg . The purpose of these scripts is to perform a VERY FASTContinue reading “Trim HLS stream with frame accuracy using ffmpeg and Bash script”

JOCHLSDownloader (Ruby gem)

The JOCHLSDownloader ruby gem is a very simple native ruby code that downloads all files linked by a m3u8 manifest (used in HLS), I have used several times for test purposes.   You can download the JOCHLSDownloader (Ruby version) from: Note: For LIVE and EVENT playlist types it downloads only the firsts media segments. For VOD playlistContinue reading “JOCHLSDownloader (Ruby gem)”