What to do when Video to MP3 refuses or fails

A stopped task names a code, a sentence, and a next step. The code is the stable part. This page maps the codes the converter uses today. A refused file produces no MP3. A failed verification produces no MP3 either.

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How to read the message

Inspection refusals happen before encoding. The page says the input was rejected before transcoding. The alert shows a code such as unsupported-audio-codec, then a sentence that names the track, then a next step such as choosing another file. There is no retry button for a refusal. The same bytes will fail the same check. Change the file, or re-encode its audio somewhere else and come back with a file that matches the formats guide.

Failures during encoding or verification use a different tone. They tell you not to save the result, and they may offer Retry from the beginning once. That retry is a new task from the original file. It is worth using when the converter program failed to load, or the worker stalled. It is not worth expecting a different answer when the audio itself fails a fixed check, such as the sample-count mismatch below. After a second failure, the same input is not retried again.

Container, duration, and size

unsupported-container means the bytes are not a supported MP4, QuickTime MOV, or WebM file. The extension was ignored. A renamed AVI, MKV, or Matroska file fails here. The next step in the message is to choose MP4 or MOV containing AAC-LC, or WebM containing Opus. MP4 is recognized from its major brand. MOV is recognized from the QuickTime brand. WebM has to identify itself both as WebM and with a WebM document type in the header. A Matroska file that merely wears a .webm name does not pass.

invalid-duration means the container has no finite positive duration. A live capture that was never finalized, or a partial recording, fails here. invalid-file-size means the selection was empty or not a legal positive size. input-too-large-for-runtime means the file is bigger than 2,147,483,647 bytes, which is the addressing limit of the current single-buffer path. A smaller file is not promised to succeed. There is still no public file-size limit.

input-probe-failed, probe-output-invalid, and input-inspection-failed mean the inspector could not produce a usable description of the file. The usual next step is to choose a complete MP4, MOV, or WebM file. If a file you know is healthy fails this way every time, write to the contact address and describe the code. Do not send the video to the server.

Codec, profile, channels, and truncated audio

no-audio-track means the container opened and contained no audio. Pictures alone are not enough. unsupported-audio-codec means an audio track is not AAC in an MP4 or MOV file, or not Opus in a WebM file. The check covers every audio track. One MP3, AC-3, Vorbis, or FLAC track beside a good track still fails the file. unsupported-audio-profile means the codec is AAC but the profile is not LC. AAC Main, and other AAC profiles, stop here. The next step is to re-encode the audio as AAC-LC, or to choose another file.

unsupported-channel-layout means the track is not exactly one of these: one channel labelled mono, two channels labelled stereo, or six channels labelled 5.1. A 5.1(side) label, an unlabelled layout, or a channel count that disagrees with the label is refused. The downmix is not applied to those files, because guessing the speaker positions would put sound in the wrong place.

invalid-audio-track means a track is missing a stream index, a sample rate, or a finite positive audio duration. input-audio-decode-failed means a track looked supported and then failed a full decode. The message calls that truncated or malformed. Export the file again from the original, or choose a complete copy. Renaming it will not repair missing samples.

Encoder and verifier failures

encoding-failed means the MP3 encoder returned a non-zero status. conversion-failed is the unexpected version of a conversion error. The next step on both is to retry from the original input once. core-load-failed means the converter program itself did not load. Check the connection to the processing site and start once more. The file was not uploaded. The page already tries that program load three times, with a pause, before it shows the error.

Verification errors include output-probe-failed, output-structure-invalid, mp3-frame-contract-failed, mp3-frame-truncated, mp3-frame-structure-invalid, source-full-decode-failed, and output-full-decode-failed. They mean the bytes that came out are not a single clean 48 kHz, 192 kbps constant-bitrate MP3 with the expected channels, or could not be decoded completely. Do not save that result. sample-count-mismatch means the decoded MP3 does not have the same number of samples per channel as the decoded source. The required difference is zero. The page tells you not to save, and to stop that input rather than keep shopping for a lucky retry.

output-empty, output-not-decoded, and duration-mismatch decide whether the encoded file can be saved. The MP3 has to be non-empty, it has to decode completely, and its decoded duration has to match the selected track. Those checks do not look for a special tone or a fixed pattern of loud passages. Ordinary speech and music are saved when they pass. A retry of the same failed output meets the same rule.

Stalls, crashes, and leaving the page

task-timeout means the worker stopped making progress during time the page counted as active and in the foreground. Time the tab spent hidden or the computer spent asleep is not counted toward that stall. The worker is terminated. No partial output is kept. A very large decode can also end this way. In one virtual-machine measurement, a noisy file of 303,150,578 bytes failed because the decoded audio was 2,400,000,000 bytes and the browser would not transfer an array that large. The page reported task-timeout. That run is not a public size limit. It is evidence that the single-buffer path can die on decoded size, not only on the size shown in a file listing.

A crash, an out-of-memory kill, or a tab that stops responding is a failed task. Reaching a high percentage is not success. There is no resume. Open the converter again and, if the button is offered, retry once from the original file. Closing other heavy tabs before that retry is the only memory advice the browser guide can honestly give. It does not guarantee the next run.

If you cancel during conversion or verification, confirm only if you mean it. The default button keeps the task. Confirming cancel drops the work. If a task finishes while the confirm dialog is open, the dialog changes to ask whether to discard the verified result. Keep result leaves it available to save.