Why does FFmpeg say it cannot use stream copy with areverse?

Filters work on decoded audio, so FFmpeg has to decode the input, reverse the samples, and encode a new file. The -c copy option skips decoding entirely, which makes it incompatible with any filter. Remove -c copy, or set a real encoder such as -c:a pcm_s16le for WAV or -c:a libmp3lame for MP3, and the command will run.

Can FFmpeg reverse audio without re-encoding it?

Not in a lossy format. Reversing an MP3 or AAC file means decoding it and encoding the result again, which costs a little detail each time. Writing the output as WAV avoids that second loss, because PCM is uncompressed. If the source is already WAV or FLAC, a reversed WAV or FLAC is fully lossless.

Does areverse keep stereo channels and the sample rate?

Yes. The filter only changes the order of the samples in time. Left stays left, right stays right, and the sample rate and channel count carry over unless you change them with other options. If you want a different rate, add -ar 44100 or similar; to fold stereo down to mono, add -ac 1.

Can FFmpeg play audio backwards without making a new file?

Yes, with ffplay, the small player that ships with most FFmpeg builds. Run ffplay -af areverse input.mp3 and it previews the reversed audio directly. It still has to load the whole clip into memory before playback starts, so on long files there will be a pause, and nothing is saved until you run the full ffmpeg command.

Is there an easier way to reverse audio than the command line?

Yes. If you only need to flip one file, a browser tool does the same job without installing anything: drop the file in, press reverse, and download a WAV. FFmpeg earns its place when you need to reverse many files, script the job, or reverse video and audio together in one pass.

How to Reverse Audio with FFmpeg (areverse, Batch, Video)

To reverse audio with FFmpeg, run ffmpeg -i input.mp3 -af areverse output.wav. The areverse audio filter flips every sample end to end and FFmpeg writes the result as a new file, leaving the original untouched. Add -vf reverse to flip a video’s picture at the same time, or wrap the command in a loop to reverse a whole folder. If you’d rather skip the terminal, a free audio reverser does the same flip in a browser tab.

What is the FFmpeg command to reverse audio?

The core command is one line:

ffmpeg -i input.mp3 -af areverse output.wav

Here -i names the input, -af applies an audio filter, and areverse is FFmpeg’s built-in filter for playing audio backwards. The output extension tells FFmpeg which format to write, so output.wav produces uncompressed PCM and output.mp3 produces an MP3 (using the LAME encoder included in most builds).

WAV is the better default. Reversing itself is lossless — it reorders samples without discarding any — but every lossy encode throws a little detail away. If your source is an MP3, decoding it, reversing it, and writing WAV means you only pay for the original encode, not a second one. Convert to MP3 once at the end if you need a smaller file.

Two common errors are easy to fix. If FFmpeg complains about filtering and stream copy, remove any -c copy from the command: filters need decoded audio, so copying the stream untouched is impossible. And if the input is a video but you only want sound, add -vn to drop the picture:

ffmpeg -i clip.mp4 -vn -af areverse clip-reversed.wav

To hear the result before saving anything, ffplay -af areverse input.mp3 previews the reversed audio directly.

How do you reverse only part of an audio file?

Trim first, then reverse. The atrim filter cuts a section by start and end time in seconds, and filters run left to right when separated by commas:

ffmpeg -i input.wav -af "atrim=start=10:end=15,asetpts=PTS-STARTPTS,areverse" section.wav

That writes seconds 10 to 15, reversed, as their own file. The asetpts step resets the timestamps so the clip starts at zero.

If you want the reversed section dropped back into place — forward, backward, forward — split the stream into three parts and join them with concat:

ffmpeg -i input.wav -filter_complex "[0:a]asplit=3[a][b][c];[a]atrim=end=10,asetpts=PTS-STARTPTS[p1];[b]atrim=start=10:end=15,asetpts=PTS-STARTPTS,areverse[p2];[c]atrim=start=15,asetpts=PTS-STARTPTS[p3];[p1][p2][p3]concat=n=3:v=0:a=1[out]" -map "[out]" output.wav

It works, but this is the point where a visual editor becomes faster. In Audacity you drag across the five seconds and choose Effect → Reverse; see how to reverse audio in Audacity. FFmpeg wins when the same cut needs to happen to dozens of files with identical timings.

How do you reverse video and audio together with FFmpeg?

Apply both filters in one command — reverse for the picture and areverse for the sound:

ffmpeg -i input.mp4 -vf reverse -af areverse output.mp4

The result plays the whole clip backwards with the soundtrack matched to the picture, the classic rewind effect. FFmpeg re-encodes the video, so expect the job to take a while on long or high-resolution clips, and set your usual quality options (such as -crf for H.264) if you care about file size.

If you want the picture reversed but the original sound playing forward, use -vf reverse alone and leave out -af areverse. For a silent reversed clip, add -an. Phone and desktop alternatives for the same job are compared in how to reverse a video.

How do you batch-reverse a folder of files?

Loop over the files and run the same command on each. In a macOS or Linux terminal (bash or zsh):

for f in *.mp3; do ffmpeg -i "$f" -af areverse "${f%.*}-reversed.wav"; done

In Windows Command Prompt:

for %f in (*.mp3) do ffmpeg -i "%f" -af areverse "%~nf-reversed.wav"

In PowerShell:

Get-ChildItem *.mp3 | ForEach-Object { ffmpeg -i $_.FullName -af areverse "$($_.BaseName)-reversed.wav" }

Each version writes a new -reversed.wav next to every source file, so nothing is overwritten. Keep the quotes around file names; without them, names containing spaces break the command. This is where FFmpeg genuinely beats every other option: reversing a folder of fifty one-shot samples for a sound pack takes a single line instead of fifty rounds of open, flip, and export.

Why does areverse use so much memory on long files?

To output the first sample of a reversed file, FFmpeg needs the last sample of the original, so areverse has to hold the entire clip in memory before it can write anything. FFmpeg’s documentation warns about exactly this and suggests trimming. The same applies to the video reverse filter, which buffers every decoded frame — far heavier than audio, and the usual reason a long video reverse runs out of memory.

For audio, the buffer is the decoded, uncompressed size — much larger than a compressed MP3 on disk. A song-length clip is no problem on a modern computer, but a multi-hour recording can get heavy on a low-memory machine.

The workaround is to reverse in chunks. Split the file into segments, reverse each one, then join the reversed segments in the opposite order:

ffmpeg -i long.wav -f segment -segment_time 300 -c copy part%03d.wav

Reverse each partNNN.wav with the batch loop above, list the reversed parts last-to-first in a text file, and join them with FFmpeg’s concat demuxer (-f concat -i list.txt -c copy). Because WAV is uncompressed, the joins are seamless.

How does FFmpeg compare with other ways to reverse audio?

Method	Cost	Install	Reverses a section?	Batch / scripting	Best for
FFmpeg	Free	Command-line tool	Yes, by timestamps	Yes	Many files, automation, video + audio
Browser tool	Free	None	No — whole file	No	One quick, private flip
Audacity	Free	Desktop app	Yes, drag-select	Limited (macros)	Precise visual edits
Reverse Audio PRO app	Free; PRO is a one-time $4.99	Phone app	No — whole recording	No	Record, reverse, and add effects on a phone

FFmpeg is the right tool when the job repeats or needs to be scripted. For a single clip, the free audio reverser is quicker: it accepts MP3, WAV, M4A, OGG, and WebM, reverses in the browser with nothing uploaded, offers an A/B compare, and downloads a free WAV. On a phone, the Reverse Audio PRO app adds speed from 0.25× to 3.0×, pitch across ±12 semitones, ten effects, and MP3/M4A export as a one-time purchase, not a subscription — see how to reverse audio on iPhone for that workflow.

Can FFmpeg make reverse-echo effects?

Yes, by sandwiching an effect between two reverses. Reverse the audio, add the effect, then reverse it again:

ffmpeg -i vocal.wav -af "areverse,aecho=0.8:0.88:60:0.4,areverse" vocal-reverse-echo.wav

The aecho filter adds repeats after each sound; because it runs on the reversed audio, those repeats land before each word once the clip is flipped back. The result is the swelling, ghostly lead-in heard in reverse-delay and pre-verb effects. Increase the delay value (in milliseconds) for longer gaps between repeats, and lower the decay for fainter ones. Because the audio is reversed twice, the vocal itself plays forward — only the echo is backwards.