Converting and upscaling AV (Analog Video), S-Video to HDMI is a common process used to modernize and improve the quality of older analog video signals for use with modern HDMI-equipped displays or devices. Here's what you should know about this process:

1. Analog to Digital Conversion: AV and S-Video are analog video formats, while HDMI is a digital format. To make these signals compatible, a conversion process is required. This conversion involves taking the analog signal and encoding it into a digital format that can be transmitted via HDMI.

2. Upscaling: Upscaling is the process of increasing the resolution of a video signal. This is particularly important when transitioning from lower-resolution analog sources to higher-resolution HDMI displays. The upscaling process interpolates and enhances the image to fit the HDMI display's resolution. However, it's important to note that upscaling does not magically increase the true quality of the source; it can only make it fit better on a higher-resolution screen.

3. Quality Considerations: The quality of the final output largely depends on the quality of the converter or upscaler being used. High-quality converters can maintain or even enhance the original picture quality, while cheaper ones may introduce artifacts and degrade the image.

4. Input and Output Ports: Check the input and output ports on your converter. Make sure it supports AV (composite video) and S-Video as inputs and HDMI as an output. Also, consider the availability of other audio outputs, as you may need to separate the audio signal.

5. Aspect Ratio and Resolution Settings: Many converters offer options to adjust the aspect ratio (e.g., 4:3 or 16:9) and resolution settings. Make sure to configure these settings according to your preferences and the capabilities of your HDMI display.

6. Audio Conversion: If you are converting both video and audio, ensure that the converter can handle the audio format of your source (e.g., stereo or mono) and is capable of transmitting audio over HDMI.

7. Compatibility: Check the compatibility of your source device with the converter. Some older AV and S-Video sources may have copy protection or other compatibility issues that can affect the conversion process.

8. Power Supply: Some converters require an external power source, while others can be powered through the HDMI connection. Ensure you have the necessary power supply if it's required.

9. Signal Latency: In some cases, there may be a slight delay (latency) in the conversion process. This can be important for applications where synchronization is critical, such as gaming. Look for converters with low latency if this is a concern.

10. User Reviews and Recommendations: Before purchasing a converter or upscaler, it's a good idea to read user reviews and seek recommendations to ensure that the product meets your specific needs and works well with your equipment.

In summary, converting and upscaling AV and S-Video to HDMI can be a useful way to bring older analog video sources into a modern digital setup. However, the quality and performance of the process can vary depending on the equipment used, so it's important to choose the right converter or upscaler for your specific requirements.