Does 3GP to MP4 upload my file or text to Tool-You servers?

No. 3GP to MP4 runs in this browser tab. Files stay on the device. Limit note: Re-encode H.264+AAC. CRF is adjustable. Decode failure is visible. Max 100 MB.

Should I use MP4 to 3GP instead of 3GP to MP4?

Use 3GP to MP4 when you need Re-encode 3GP into MP4. Use MP4 to 3GP when you need Encode MP4 for older 3GP phones. They share a category (Video) but not the same job.

What are the limits of 3GP to MP4?

Re-encode H.264+AAC. CRF is adjustable. Decode failure is visible. Max 100 MB. Also: Local ffmpeg.wasm re-encode of 3GP into H.264+AAC MP4. Not a lossless remux; decode failure is shown instead of a fake file.

3GP to MP4

Re-encode 3GP into MP4.

Local ffmpeg.wasm re-encode of 3GP into H.264+AAC MP4. Not a lossless remux; decode failure is shown instead of a fake file.

What 3GP to MP4 does

Local ffmpeg.wasm re-encode of 3GP into H.264+AAC MP4. Not a lossless remux; decode failure is shown instead of a fake file.

Practical limit for 3GP to MP4: Re-encode H.264+AAC. CRF is adjustable. Decode failure is visible. Max 100 MB. That is why output can differ from heavy desktop Video software. Read the tool-specific note again: Local ffmpeg.wasm re-encode of 3GP into H.264+AAC MP4. Not a lossless remux; decode failure is shown instead of a fake file.

How to use 3GP to MP4

Stay on this 3GP to MP4 page (/3gp-to-mp4). Do not switch to MP4 to 3GP unless you actually want Encode MP4 for older 3GP phones..
Add the file type 3GP to MP4 accepts. Hint from the path: 3gp to mp4. Re-encode 3GP into MP4.
Set only the options that match 3GP to MP4. Neighbor Compress Video does something else (Shrink an MP4 in the browser.). Tool note: Local ffmpeg.wasm re-encode of 3GP into H.264+AAC MP4. Not a lossless remux; decode failure is shown instead of a fake file.
Run 3GP to MP4 in this tab. Browser memory still applies: Re-encode H.264+AAC. CRF is adjustable. Decode failure is visible. Max 100 MB.
Download or copy the result from 3GP to MP4. If it is the wrong job, open MP4 to 3GP instead.

When not to use 3GP to MP4

Skip 3GP to MP4 when a neighbor tool matches better — start with MP4 to 3GP or Compress Video — or when the description already warns the job will fail. In the tool’s own words: Local ffmpeg.wasm re-encode of 3GP into H.264+AAC MP4. Not a lossless remux; decode failure is shown instead of a fake file.

Questions about 3GP to MP4

What does 3GP to MP4 do that other Video pages on this site do not?: Local ffmpeg.wasm re-encode of 3GP into H.264+AAC MP4. Not a lossless remux; decode failure is shown instead of a fake file. Short version: Re-encode 3GP into MP4.
Does 3GP to MP4 upload my file or text to Tool-You servers?: No. 3GP to MP4 runs in this browser tab. Files stay on the device. Limit note: Re-encode H.264+AAC. CRF is adjustable. Decode failure is visible. Max 100 MB.
Should I use MP4 to 3GP instead of 3GP to MP4?: Use 3GP to MP4 when you need Re-encode 3GP into MP4. Use MP4 to 3GP when you need Encode MP4 for older 3GP phones. They share a category (Video) but not the same job.
What are the limits of 3GP to MP4?: Re-encode H.264+AAC. CRF is adjustable. Decode failure is visible. Max 100 MB. Also: Local ffmpeg.wasm re-encode of 3GP into H.264+AAC MP4. Not a lossless remux; decode failure is shown instead of a fake file.