Convert SEC to AVI

A CCTV recorder may save footage as a proprietary .sec backup that common players and editors cannot open. Converting it to .avi makes the recording usable in legacy Windows software, evidence systems, or applications that specifically require AVI.

What the SEC format is

SEC is not one standardized video format. The extension is commonly associated with proprietary backups from Samsung DVR and NVR systems, although other surveillance manufacturers may use it differently. An SEC backup can include video from one or several camera channels, audio, timestamps, indexes, authentication data, and other files required by the vendor's player.

SEC files are typically created when an operator exports a time range from a security recorder to a USB drive or computer. Windows Media Player, VLC, and FFmpeg generally cannot decode an SEC file directly because the extension does not identify a universal container and codec combination. Keep the complete exported folder: the SEC file may depend on companion index, metadata, or player files.

What the AVI format is

AVI is a Microsoft container supported by many older Windows applications, editors, and playback systems. It can contain different video and audio codecs, including Motion JPEG, MPEG-4 Part 2, and uncompressed PCM audio, so an AVI file's compatibility and size depend on the codecs selected during export.

AVI is appropriate when the receiving system specifically requires it. It is not inherently higher quality or smaller than SEC, and modern MP4 with H.264 video and AAC audio is usually more efficient when AVI is not mandatory.

How to perform the conversion

Use the recorder's manufacturer software

1. Identify the DVR or NVR manufacturer and model from the recorder label, export folder, or original backup documentation.
2. Install the playback or backup utility supplied for that model. Older Samsung systems may use Samsung Smart Viewer or a model-specific Backup Viewer; current software availability depends on the recorder and manufacturer.
3. Open the backup through File → Open or the utility's backup playback screen. Select the complete exported folder if opening only the SEC file produces an error.
4. Select the required camera channel and time range, then choose Export, Save As, or Convert. Select AVI if the utility offers it.
5. Use the source resolution and frame rate where available. Enable audio, timestamps, and camera identifiers only when needed; overlays may be permanently embedded in the output.
6. Open the AVI in VLC or the intended editor and check its beginning, middle, and end, including audio, timestamps, frame rate, and every required channel.

The vendor utility is the preferred method because it understands the proprietary video structure and any recorder-specific authentication. If it exports only MP4 or another standard format, save that file first and transcode it to AVI with FFmpeg.

Transcode the exported standard video

After obtaining a readable MP4, use FFmpeg to create a broadly compatible Motion JPEG AVI with PCM audio:

ffmpeg -i exported.mp4 -c:v mjpeg -q:v 3 -c:a pcm_s16le output.avi

Motion JPEG and PCM are widely supported but can create very large files. If the receiving application supports MPEG-4 Part 2, use a smaller AVI instead:

ffmpeg -i exported.mp4 -c:v mpeg4 -q:v 3 -c:a libmp3lame -b:a 128k output.avi

VLC can transcode a readable intermediate file through Media → Convert/Save, but its AVI profiles and codec support vary by build. Current HandBrake versions are useful for creating MP4 intermediates but generally do not provide AVI output, so it is not a direct AVI solution.

Online conversion services

CloudConvert and Convertio can convert an already-exported MP4 to AVI when their current format options include AVI. Direct SEC uploads usually fail because these services do not include the required recorder-specific decoder. Surveillance footage may contain personal or evidentiary information, so do not upload it unless the service's storage, retention, and privacy terms are acceptable.

Quality and compatibility limitations

• Conversion cannot restore detail, audio, or frames missing from the original recording. Increasing output resolution or bitrate only increases file size.
• Some vendor utilities export the original stream; others render a playback view or screen capture. Rendering can reduce frame rate, remove audio, or burn timestamps and controls into the image.
• For legal or investigative use, retain the original SEC backup and all companion files. Treat the AVI as a working copy because transcoding can alter timestamps, frame timing, metadata, and compression.
• AVI is a container rather than a single codec and has practical limitations with large files, modern codecs, and variable-frame-rate footage. Use MP4 instead when the recipient does not explicitly require AVI.
• Password protection, encryption, recorder-specific formatting, or file damage may prevent conversion by anything except the original recorder or its matching manufacturer software.
• Renaming .sec to .avi changes only the filename; it does not convert the video.