Convert TMP to AVI

A temporary video file may need to be delivered to an older editor, DVR system, or Windows application that accepts AVI but not the source format. This is possible only when the .tmp file contains a complete, readable media stream.

What a TMP file is

.tmp is a generic temporary-file extension, not a video format. Video editors, screen recorders, CCTV/DVR software, download managers, browsers, and export tools may use it for media being recorded, cached, downloaded, or rendered.

A TMP file can contain AVI, MP4, MPEG program or transport streams, proprietary recorder data, partial metadata, or no video at all. The extension alone cannot identify its contents or establish that conversion is possible.

Copy the file before testing it, especially if the originating application may still be writing to it. If the program that created it is available, stop the recording normally or use its recovery/export function first; temporary recordings are often incomplete until the application closes the file.

Inspect the copy with MediaInfo or FFmpeg. In MediaInfo, open the file and select View → Tree or View → Text. From a command prompt, use ffprobe -hide_banner input.tmp. Reported video and audio streams indicate that conversion may work; no detected streams usually means the file is incomplete, encrypted, proprietary, or not media data.

What AVI is

AVI is a Microsoft RIFF-based multimedia container. It can store video and audio encoded with codecs such as MJPEG, DV, MPEG-4 Part 2, uncompressed video, and PCM audio.

AVI remains useful for older Windows software, legacy editors, and devices that explicitly require it. Compatibility depends on the codecs inside the AVI, not on the .avi extension: an application may reject AVI files containing H.264, AAC, variable frame rate video, or codecs it does not install or support.

MJPEG video with PCM audio is a common compatibility-oriented choice, but produces large files. MPEG-4 Part 2 video with MP3 audio can reduce size when the receiving program supports those codecs. AVI is generally less space-efficient and less flexible than MP4 or MKV for modern playback and archiving.

Convert a readable TMP file

FFmpeg is the most reliable desktop option because it can probe unusual inputs and explicitly select AVI-compatible codecs. It usually detects media from file contents, so renaming is unnecessary; if a program refuses the TMP extension, rename a copy only after MediaInfo identifies the underlying format.

First try a stream copy when the detected codecs are suitable for the destination application:

ffmpeg -i input.tmp -c copy output.avi

This remuxes without re-encoding, so it is fast and does not reduce quality. It can fail, or create an AVI that the target cannot play, when the source streams are unsuitable for AVI or the destination software.

For broad legacy compatibility, re-encode to MJPEG and PCM:

ffmpeg -i input.tmp -c:v mjpeg -q:v 3 -c:a pcm_s16le output.avi

For a smaller file where MPEG-4 Part 2 and MP3 are accepted:

ffmpeg -i input.tmp -c:v mpeg4 -q:v 3 -c:a libmp3lame -b:a 192k output.avi

Lower -q:v values produce higher-quality, larger video. Match the destination system's required resolution, frame rate, video codec, audio codec, and file-size limit rather than relying on a generic AVI preset.

VLC can be used when the file plays in VLC: select Media → Convert / Save → Add, choose Convert, select or create a profile with AVI encapsulation and the required codecs, set an output name ending in .avi, and start conversion. Verify the generated file in the receiving application; VLC profiles differ by version.

HandBrake is not an AVI solution because its normal output formats are MP4, MKV, and WebM. Online services such as CloudConvert and FreeConvert may process readable TMP-based video, but upload only non-sensitive files and check file-size limits. If their upload detection fails, upload a copy renamed to the media format identified by MediaInfo.

Recovery and compatibility limits

Renaming input.tmp to input.avi does not convert it. It works only when the TMP file already contains a valid AVI stream and its original extension was temporary.

Errors such as moov atom not found, Invalid data found when processing input, or missing indexes usually indicate an unfinished or damaged recording. MP4-based temporary files are especially difficult to recover because their moov metadata is commonly written when recording ends; the original recorder may be required to finalize or repair the file.

Keep the source until the AVI has been opened and checked in the destination software. Re-encoding cannot restore frames, audio, or metadata absent from an incomplete TMP file.