Convert STRG to AVI

Some Novus surveillance systems and their playback software save recordings as .strg, while legacy editors or devices may require AVI. Converting the file creates a more widely accepted copy for playback or editing, but the original recorder software is usually required to decode STRG.

What the STRG format is

In the Video category, STRG is a proprietary surveillance-video format associated with Novus recording systems and software such as Novus Management System (NMS) and E-Viewer. It is not a standardized container with one publicly defined codec; the recording may include a vendor-specific index, timestamps, camera information, or other data that general-purpose media tools cannot interpret.

Changing recording.strg to recording.avi only changes the filename extension. It does not convert the video, and it can prevent the vendor application from recognizing the file.

What AVI is

AVI is Microsoft’s RIFF-based audio-video container. Older Windows players, editors, and hardware devices support it, and it can contain codecs such as Motion JPEG, MPEG-4 Part 2, or uncompressed video.

AVI is useful when a legacy application specifically requires that container. It is usually less storage-efficient than an H.264 or H.265 MP4, and converting to AVI cannot restore detail lost in the original recording.

Convert with the original recorder software

1. Install NMS, E-Viewer, or the playback/export application supplied for the recorder that created the STRG file. Use the matching or nearest supported version when possible.
2. Open the file from the program’s File → Open, import, or archive command rather than renaming it or opening it directly in a generic player.
3. Choose Export, Save as, or Convert. Select AVI if it is available as an output format.
4. Use the original resolution and frame rate. Select Motion JPEG or MPEG-4 Part 2 when the software offers a codec choice; these are generally more compatible with older AVI applications than newer codecs.
5. Export to a new file and test the beginning, middle, and end. Check video, audio, synchronization, timestamps, camera labels, and event markers before deleting or moving the STRG source.

This is the preferred method for protected or proprietary recordings because the vendor software can read the STRG index and decode its video. Some applications export only a standard intermediate file such as MP4; that file can then be converted to AVI with desktop software.

Test the file with FFmpeg

FFmpeg can convert STRG only if the file contains a stream and codec that FFmpeg recognizes. Test it with:

ffprobe -hide_banner recording.strg

If the output lists a video stream and a supported decoder, create an AVI using MPEG-4 Part 2 video and MP3 audio:

ffmpeg -i recording.strg -map 0:v:0 -map 0:a:0? -c:v mpeg4 -q:v 3 -c:a libmp3lame -q:a 2 recording.avi

For editing applications that prefer intraframe video, use Motion JPEG with uncompressed PCM audio instead:

ffmpeg -i recording.strg -map 0:v:0 -map 0:a:0? -c:v mjpeg -q:v 3 -c:a pcm_s16le recording.avi

Motion JPEG and PCM produce much larger files. The MPEG-4 Part 2 and MP3 combination is smaller but may not work in every old AVI application.

Errors such as Invalid data found when processing input, Unknown format, or an unsupported codec indicate that the STRG file is proprietary, encrypted, incomplete, or otherwise unreadable by FFmpeg. Changing codecs or renaming the extension will not fix that; use the recorder’s export function or obtain an unprotected standard-format export.

Online conversion

Services such as CloudConvert or Convertio can be tried only if the service explicitly accepts the STRG file and the recording is not confidential. STRG is not consistently supported as an upload format, and surveillance footage may contain personal or sensitive information. An online converter is unlikely to decode a file that NMS or E-Viewer is required to open.

Quality and compatibility limits

• Re-encoding can reduce quality. Keep the original STRG file as the evidence or archival copy and treat AVI as a working export.
• AVI identifies a container, not a single codec. An AVI may play in one application and fail in another if its video or audio codec is unsupported.
• Preserve the source resolution and frame rate; upscaling adds no recorded detail.
• Standard AVI export may omit vendor-specific timestamps, event markers, camera identifiers, authentication data, or other metadata.
• Check audio synchronization and frame timing after export, particularly with long surveillance recordings or footage containing variable frame rates.