Add JPEG quality adjustment via quality parameter

[streamthing]

This pull request introduces the ability to adjust JPEG quality in the FFmpeg-based processing pipeline by adding a quality parameter. The value of this parameter is directly passed to -q:v in FFmpeg, allowing users to control the output image compression level.

Changes

1. Modified internal/ffmpeg/jpeg.go

• Added a quality variable to parse query parameters.
• Implemented logic to append -q:v {quality} to the FFmpeg arguments if the parameter is provided.

2. Updated README.md

• Added documentation for the new quality parameter, explaining that it allows users to change the JPEG quality (e.g., quality=1).

Usage Example

Users can now control the JPEG compression level via a URL query parameter:

http://<go2rtc_ip>:1984/api/frame.jpeg?src=camera&quality=1

Where:

• quality=1 → Highest quality, larger file size.
• quality=31 → Lowest quality, smaller file size.

Why this change?

This update provides greater flexibility in adjusting image quality and file size based on user needs, making the API more versatile.

[felipecrs]

This is awesome. Maybe in future we can support also resolution (or width and height) to avoid unnecessary data transfer while requesting a small icon, for example.

[felipecrs]

Nevermind... it's already supported. 😅