Supported Formats | MP4ToMP3.tools
The tested input containers, codecs, output formats and local size limits.
Last updated 2026-09-11
Support is based on formats exercised in automated and real-browser testing. A matching extension alone is not enough: a container can hold codecs that are not in this verified matrix.
Tested input matrix
| Input container | Tested video | Tested audio | Available public tools |
|---|---|---|---|
| MP4 | H.264 | AAC | MP4 to MP3, MP4 to WAV, MP4 to M4A, Video to MP3, Extract Audio |
| MOV / QuickTime | H.264 | AAC | MOV to MP3, Video to MP3, Extract Audio |
| WebM | VP9 | Opus | WebM to MP3, Video to MP3, Extract Audio |
The converter does not claim support for every codec that MP4, MOV or WebM can contain. Files with no audio track, a damaged container or an unsupported codec return an error instead of being uploaded elsewhere.
Tested outputs
- MP3 transcoding at 128, 192, 256 or 320 kbps, with Auto, 44.1 kHz or 48 kHz sample rate and Auto, Mono or Stereo channels.
- WAV with 16-bit PCM from tested H.264/AAC MP4 files, with Auto, 44.1 kHz or 48 kHz sample rate and Auto, Mono or Stereo channels.
- Original AAC stream copy into an M4A container where compatible.
- Original Opus stream copy into an Ogg Opus file where compatible.
Stream copy uses the existing compatible audio packets and does not improve their quality. MP3 conversion decodes and re-encodes audio, so it is not lossless. WAV stores decoded audio as uncompressed PCM; it cannot recover detail already lost in the source. Use MP4 to WAV when an editor needs PCM audio.
Use MP4 to M4A to copy AAC from an MP4. Its first audio track must be AAC; it rejects other audio codecs without automatically changing the output format. For compatible AAC in MOV or Opus in WebM, choose Original audio in Extract Audio from Video.
Optional audio segments
For MP3 and MP4 to WAV, choose a file and enable Trim audio in Advanced
settings. Enter start and end times in seconds or hh:mm:ss, within the video
length and at least 0.1 seconds apart. The result player previews the extracted
segment. MP3 may include a small amount of encoder padding.
The browser must provide a usable duration. Some WebM recordings have no fixed duration; these can still be converted in full. Original AAC/M4A and Opus extraction keep the complete first audio track and do not offer trimming.
Trimming does not bypass file-size limits. The full input may still enter browser memory, and reaching a late start time can require processing earlier audio.
File-size and memory boundary
The internal public limits are up to 500 MiB on desktop and 200 MiB on mobile. They are soft limits, not a completion guarantee. Browser and device memory may be lower, and local conversion temporarily needs memory for the input, WebAssembly runtime and output.
WAV has a separate output safety limit: the result must stay below 128 MiB on desktop or 64 MiB on mobile. Conversion stops with an error if it reaches this limit; a partial WAV is never offered as a successful download.
Start with the dedicated MP4 to MP3 converter, MOV to MP3 converter or WebM to MP3 converter, or use Video to MP3 for the tested multi-container input set.