César Alonso
Verified Expert in Engineering
Telecommunication Engineer and Developer
Madrid, Spain
Toptal member since October 9, 2025
César is a telecommunication engineer with a passion for audio and video processing algorithms. He has over 20 years of experience in software development using MATLAB, C/C++, and Python for Windows and Linux desktop, mobile, and embedded platforms. César is creative, disciplined, methodical, and motivated to contribute to solving challenging problems.
Portfolio
Experience
- DSP - 20 years
- Software Development - 20 years
- MATLAB - 20 years
- Audio - 20 years
- C++ - 15 years
- Embedded C - 10 years
- Music technology - 10 years
- Machine Learning - 5 years
Preferred Environment
Linux, Windows, MacOS, Visual Studio Code (VS Code), Jira, MATLAB, Embedded C
The most amazing...
...thing I've developed is a sound recognition app for people who are hard of hearing that always runs on a smartphone with minimal power consumption.
Work Experience
Audio/Software Engineer
Synervoz Communications
- Designed and implemented DSP solutions, focusing on noise and echo cancellation on mobile and embedded platforms such as Android, iOS, and Mediatek's Airoha SoC, including the integration of AI modules for noise reduction.
- Designed and oversaw the audio algorithms testing infrastructure.
- Developed an algorithm in MATLAB to detect, record, and count heartbeats using a smartphone. Ported it to C++ for iOS.
Principal Algorithm Engineer
Cirrus Logic
- Headed the porting of voice biometrics and other voice processing algorithms from MATLAB prototypes to productizable C code for different mobile and embedded platforms.
- Designed and oversaw the best software development practices in the research team for algorithm testing and maintenance.
- Authored and co-authored several World Intellectual Property Organization (WIPO) and USA patents, presented a paper and a poster at the Cirrus Logic Innovation Conference 2019.
Senior Software and Algorithm Developer
Agnitio
- Optimized Agnitio's voice biometrics algorithm prototype into a productizable C++ version to achieve minimal memory and computation requirements.
- Played a key role in Cirrus Logic's acquisition of Agnitio's IP to offer their customers, such as Apple, voice biometrics capabilities on a chip.
- Collaborated with the research engineers to design or improve the testing infrastructure of our audio processing and ML algorithms.
Software/Algorithm Engineer
SAPEC
- Developed a novel motion-compensation algorithm that evolved into being state-of-the-art in terms of performance and computational cost.
- Contributed to developing our own MPEG2-compliant real-time video encoding chip, which removed the cost of licensing the technology for some of our products.
- Contributed to designing the video quality testing infrastructure to keep track of incremental improvements on the video encoding algorithm.
Experience
Fonid | An App to Identify Sounds for the Deaf
The key to providing always-on operation without compromising all-day battery life is a combination of proprietary audio processing and machine learning algorithms that achieve high-accuracy identification with very low computational cost. Such an all-day, always-on operation would not be feasible by performing the sound identification on a cloud server due to the power consumption of the audio data transmission itself (comparable to that of an all-day-long phone call).
Additionally, performing sound identification locally on the device avoids the privacy issues associated with continuously sending recorded audio to the cloud.
Education
Master's Degree in Sound and Music Computing
Pompeu Fabra University - Barcelona, Spain
Master's Degree in Telecommunication Engineering
University of Valladolid - Valladolid, España
Certifications
Machine Learning
Massachusetts Institute of Technology
Skills
Libraries/APIs
TensorFlow
Tools
MATLAB, Logic Pro, Git, Slack, Jira, Notion, VirtualBox, Android NDK, Jenkins, Gerrit, Claude
Languages
Embedded C, Python, C++, Java, VHDL
Platforms
Visual Studio Code (VS Code), Linux, Windows, MacOS, Android
Paradigms
Radio Frequency (RF) Protocol
Other
Digital Signal Processing, Software Development, Audio, DSP, Real-time Audio Processing, Audio Codecs, Audio Processing, ARM, Embedded Systems, HAL, Beamforming, Wearables, Artificial Intelligence (AI), Machine Learning, Deep Learning, Business Administration, Video Compression, Video Encoding, 2D Image Processing, Video Codecs, Video Processing, API Integration, Large Language Models (LLMs), Integration, Third-party Integration, State Machines, Android Development, Speech Recognition, Networks, Communication Theory, Music technology, Innovation Management, SIMD, Real-time Operating System (RTOS), Oscilloscopes & Tester Equipment, Sensors & Actuators
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