Which audio files can Reverse Audio convert?

It accepts common MP3, WAV, M4A, AAC, Ogg, and WebM audio up to 50 MB, provided the browser can decode it and the decoded audio is no longer than five minutes, has one to eight channels, uses an 8,000–192,000 Hz sample rate, and stays within 30 million total channel samples.

Does the result keep the original MP3 or M4A encoding?

No. The result is always a newly encoded PCM16 WAV. The original codec, compressed bitrate, tags, artwork, and container metadata are not retained.

Are audio files uploaded when using Reverse Audio?

No. File reading, Web Audio decoding, sample reversal, WAV encoding, and preview creation happen locally in the current browser tab, and the file bytes, decoded samples, filename, and result are not uploaded to Lizely.

Why might a listed format fail to decode?

Codec support varies by browser and operating system. A familiar container can contain an unsupported codec, so the tool reports a decode error when the current browser cannot read the file.

Does stereo audio remain stereo?

Yes. Each accepted channel is reversed independently and then written in interleaved WAV frame order, while the decoded channel count and sample rate are retained.

Convert Audio Backwards and Download a PCM16 WAV

Converting audio backwards means reversing every decoded channel sample and exporting the result as a new PCM16 WAV file. In practical terms, the download runs from the source recording’s ending toward its beginning, so a sound near the end becomes an early sound in the reversed timeline.

The browser-based Reverse Audio tool performs that conversion locally in the current tab. You can preview the source, create the reversed recording, inspect it, and download it. The file bytes, decoded samples, filename, and result are not uploaded to Lizely.

convert audio backwards — Convert Audio Backwards and Download a PCM16 WAV

What changes in a backwards conversion

Reverse Audio operates on decoded sample data instead of changing a playback setting. It reverses the sample sequence in every channel, preserves the number of frames, and writes those sequences into a new WAV file. For stereo input, the left channel is reversed independently, the right channel is reversed independently, and the two channels are interleaved again in the correct WAV frame order. The channels are not swapped.

Within the supported limits, the decoded duration, sample rate, and channel count are retained. An event near the source’s end appears near the beginning of the result, while the source’s first frame becomes the final frame. This is an audio-only operation: it does not reverse the picture in a video or convert separate video and sound tracks.

Reversal also has clear boundaries. The tool does not normalize loudness, remove silence, intentionally change pitch, stretch time, or repair clipped peaks. It also does not add fades, trim passages, preserve container metadata, or provide mastering controls. Use an audio editor when those operations are part of the finished job.

Convert audio backwards in four steps

Choose a supported audio file. Select an MP3, WAV, M4A, AAC, Ogg, or WebM file no larger than 50 MB. The file picker and decoder perform separate checks, so a recognized extension or MIME type does not guarantee that the current browser can decode the codec inside the file.
Preview the original if useful. The built-in browser preview lets you hear the source before changing its direction. Listening to the ending is especially helpful when the reversed result will be used for a transition, sound-design experiment, or speech effect.
Select Reverse audio and wait. The tool decodes the file with the browser’s Web Audio system, reverses every decoded channel locally, and creates a new WAV result. It does not call a conversion server or install FFmpeg.
Preview, verify, and download. Listen to the beginning and end of the reversed result, confirm the duration and displayed audio properties, and then download the explicitly labeled PCM16 WAV.

Check the input limits first

The compressed file-size limit and the decoded-audio limits apply at different stages. Passing the 50 MB file check does not guarantee that the decoded recording is short enough or small enough to process.

Check	Supported value	What happens outside the range
Compressed input size	50 MB maximum	A larger file is rejected before conversion.
Decoded duration	5 minutes or shorter	Longer decoded audio is rejected rather than truncated.
Decoded channel count	1 to 8 channels	Audio with more than eight channels is rejected.
Decoded sample rate	8,000 to 192,000 Hz	A sample rate outside the range is rejected.
Total channel samples	30 million maximum	Decoded arrays above the budget are rejected in full.

The channel-sample budget equals the number of frames multiplied by the number of channels. It protects the browser tab from unexpectedly large decoded arrays, which is why a compact compressed file can still exceed a decoded limit. If any accepted limit is crossed, the tool displays a specific message and does not partially process the recording. Changing the file or retrying also clears the previous download so that an older success cannot be mistaken for a new result.

Codec support depends on the visitor’s browser and operating system, and a familiar container may hold a codec the browser cannot decode. When Web Audio rejects the data, the tool reports a decode error instead of pretending the conversion succeeded. The browser reads accepted input into an ArrayBuffer and uses Web Audio for decoding; [MDN’s decodeAudioData reference](https://developer.mozilla.org/en-US/docs/Web/API/BaseAudioContext/decodeAudioData) provides details about that browser API.

Compare the source with the WAV download

Reversing the timeline and exporting a new file are separate parts of the process. The following comparison shows what stays the same and what necessarily changes during the export.

Aspect	Original file or decoded source	Downloaded result
Timeline	Normal forward sample order	Every channel’s sample order is reversed
Duration	Decoded recording length	Retained
Sample rate	Decoded rate within the supported range	Retained
Channels	Decoded layout with one to eight channels	Retained, with stereo channels independently reversed and interleaved
Encoding	MP3, WAV, M4A, AAC, Ogg, or WebM input decoded by the browser	A newly encoded PCM16 WAV
Metadata	The source may contain tags, artwork, chapters, or container fields	Original metadata is not copied
Sample representation	Browser-decoded floating-point samples	Clipped and converted to signed 16-bit little-endian PCM

The output is never the original MP3, M4A, AAC, Ogg, WebM, or compressed WAV stream with its playback direction changed. Each decoded floating-point sample is clipped to the range from -1 to 1 before it is mapped to signed 16-bit PCM. Negative full scale maps to -32768, positive full scale maps to 32767, and the PCM bytes are written little-endian. This conversion can reduce numerical precision, and the resulting WAV may be much larger than a compressed source.

The reversal preserves the decoded duration, sample rate, channel count, and frame count, but it does not promise that the final numeric values are identical to the source because of PCM16 clipping and quantization. Album art, tags, chapters, loop markers, encoder settings, compressed bitrate, and container-specific fields are not carried into the download.

Verify the reversed recording

A successful preview shows that the browser can play the result, but it does not replace a final check in the place where the audio will actually be used.

Keep the source file. It provides a direct reference for comparing the beginning and ending of the reversed version.
Listen to both ends of the result. The source’s final sounds should now appear at the start, and its opening sounds should appear at the end.
Confirm the displayed properties. Check the duration, channel count, sample rate, and output file size shown by the tool.
Open the downloaded WAV in its destination. Browser preview success does not guarantee that every older device supports the same WAV channel layout or a high sample rate, so test the actual download in the intended editor or player.

For a reversed transition, listen to the exact point where the reversed section will meet the next clip. For reversed speech or a sound-design experiment, compare the result with the original to confirm that the intended ending is now the starting point. Keeping both versions makes it easier to identify an accidental decode, truncation, or mismatched edit before the WAV enters a larger project.

Match the workflow to the result you need

Sample reversal can be useful for sound-design experiments, reverse speech, transition effects, sample inspection, and hearing the end of a recording from a different perspective. These uses depend on changing the order of the existing audio rather than adding new creative processing.

If the finished project still requires fades, trimming, codec selection, metadata preservation, intentional pitch changes, time stretching, loudness normalization, silence removal, clipping repair, or mastering controls, complete those tasks in an audio editor. If the reversed recording also needs an exact time range, Audio Cutter is not part of the Reverse Audio workflow.

For the narrow task of playing existing audio from end to beginning and saving it as a new file, the standard workflow is straightforward: choose a decodable source, run the local reversal, check the resulting WAV, and test the download in its intended application.