Author Archives: Jordi Cenzano

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)”

Loudness meters [CAT]

These slides are part of a conference that we gave about loudness (link). Different views of loudness were explained in that conference: Introduction by Llorenç Gómez (TVC) Standards by Josep Ramon Casas (UPC) Loudness meters by Jordi Cenzano (8TV) Loudness in production chain by Emili Planas (Mediapro) The conference was organized by Consell del AudiovisualContinue reading “Loudness meters [CAT]”

Design and implementation of a loudness monitoring system – MERIT master thesis

This paper was created in 07/2013 as MERIT master thesis (from UPC university). The main objective is to explore the normalization of audio levels in the media industry, which is a relevant issue nowadays. Many broadcast organizations around the world are concerned about this problem and they have published many papers and standards that are analyzed in this project, some of thoseContinue reading “Design and implementation of a loudness monitoring system – MERIT master thesis”

Shape from silhouette and camera model slides

This slides explains how to calculate the camera intrinsics matrix, camera extrinsics matrix, and camera projection matrix from camera model. And you can find an introduction of SFS (Shape From Silhouette) method.

Object labeling in a multicamera environtment

In this paper I describe an algorithm that it can relate objects from different images of the same scene. This algorithm needs like starting point the mask images from N full calibrated cameras. The algorithm is able to identify different objects presents in the scene and it can correlate these objects from one picture toContinue reading “Object labeling in a multicamera environtment”