Corrupted MP4 Files

Question

Corrupted MP4 Files

Bryce Valdespino 0

I have an application called Medal which saves clips from games. I have saved various funny and memorable moments with myself and with friends so they mean a lot to me. One day I was trying to transfer the files to a larger drive. I made a dumb mistake and deleted the original folder thinking I had copied all of the files into the new folder and I didn't and without realizing I emptied my recycling bin.

For a while I went through some trials and tribulations and used a free software that recovered my files, however whenever I play them they aren't playing. I downloaded VLC and used some other applications and websites to fix them as well but none of them worked.

I just want some help to figure out how to get them back and working. Preferably I would like a free method to fix my problem, but if something requiring a payment is necessary then I will proceed with that.

0 comments

2 answers

Your answer

Answer 1

First, try repairing the recovered videos by rebuilding their file structure using a reference clip recorded with the same app/settings, since the issue is likely missing or damaged metadata rather than full data loss. Make sure the files aren’t overwritten and test them in VLC after any repair attempt to confirm playback. If you need a straightforward way to do this, you could try video repair tools from Remo Software and EaseUS, as it’s designed specifically for fixing unplayable recovered MP4 files like yours.

Answer 2

Francisco Montilla 30,260 Independent Advisor

Hi Bryce, I know how painful this feels.

The most effective first fix for recovered MP4s that will not play is to rebuild their missing header using an open source tool called untrunc. It repairs MP4s by borrowing a clean header from a short good clip recorded with the same app and settings. Here is exactly how to do it on Windows.

Open Medal and record a few seconds with the same game and the same recording settings you used for the lost clips. Keep this file safe. Name it good.mp4.

Now get untrunc for Windows from its official GitHub releases, then extract it to a simple folder such as C:\Tools\untrunc. Put good.mp4 and one of your broken files in that same folder. Always work on copies of the recovered files, not the originals.

Now open Windows Terminal or Command Prompt, cd to that folder, then run this command exactly:

untrunc.exe good.mp4 broken.mp4

If it works, you will see a new file alongside the original with a repaired header that should open in Movies and TV or VLC. If you have many files, you can repeat the command for each one. To speed that up you can use this simple loop:

for %f in ("C:\Recovered*.mp4") do C:\Tools\untrunc\untrunc.exe C:\Tools\untrunc\good.mp4 "%f"

That will attempt a repair on every MP4 in C:\Recovered using your good.mp4 as the template.

A few quick tips while you do this:

Only try to repair files that are a realistic size for a clip. If a file is a few kilobytes, there is no video data left to salvage. If a file is hundreds of megabytes, untrunc has a good chance.

Do not save anything new to the drive the clips were deleted from. Writing new data can overwrite pieces the recovery tool already found, which makes repairs impossible.

Always verify by opening the repaired file in a player and scrubbing around. If audio works but video does not, or vice versa, try a second short reference clip from Medal using the exact same resolution and encoder option as before.

If untrunc reports that it cannot find usable video or audio streams, that usually means the recovery tool pulled back fragments only. In that case the next step would be a deeper pass with an open source carver and then a different repair path. Tell me what happens with untrunc and I will guide you to the next best move.

Bryce Valdespino 0 Reputation points

2025-11-20T19:21:44.2566667+00:00

For both Command Prompt and Windows Terminal it said that untrunc was not found even though I set it up as you said. I also tried to run it to see if that was a problem and it still didn't work.
Francisco Montilla 30,260 Reputation points Independent Advisor

2025-11-20T19:54:35.47+00:00
Hi Bryce,

If you didn't do it yet, open the ZIP file and move the only folder inside to your Downloads folder. Inside the folder you should see some .dll files and an untrunc.exe file

Make sure your cmd/terminal window is in the same folder as your untrunc.exe file.

For example, If your executable is stored in C:\Users\Bryce\Downloads\untrunc_x64, do:

cd "C:\Users\Bryce\Downloads\untrunc_x64"

Then, type untrunc.exe and press TAB. Now you will see an autocompleted command that is either untrunc.exe (for cmd) or .\untrunc.exe (for PowerShell). That's the correct base command you will use for my previous instructions.

Don't worry if you get stuck again. If needed, just share some screenshots with me and I'll tell you how to proceed further.
Bryce Valdespino 0 Reputation points

2025-11-20T22:44:14.49+00:00

Never mind I see your recent answer now. I only saw it after commenting this.
Bryce Valdespino 0 Reputation points

2025-11-20T22:59:42.9066667+00:00

This helped, it went through with the process. However, when I opened the fixed file it was the same as the broken file - it would open but nothing would play.
Francisco Montilla 30,260 Reputation points Independent Advisor

2025-11-21T21:46:32.71+00:00
Got it, Bryce.

If untrunc runs but the result still will not play, the file usually has damaged timestamps or a broken index. The next move is a pure open source remux with FFmpeg that regenerates missing timestamps and writes a clean container.

Install an official FFmpeg build, extract it to a simple path like C:\Tools\ffmpeg, then open Windows Terminal in that folder. Put one broken clip in the same folder or reference it by full path. Run this first pass that keeps audio and video without re-encoding while generating timestamps:

ffmpeg -err_detect ignore_err -analyzeduration 200M -probesize 200M -i "broken.mp4" -map 0:v:0? -map 0:a:0? -c copy -fflags +genpts "repaired.mkv"

If repaired.mkv opens and you can scrub, you are done. If it opens but stays black or stalls, try a gentle re-encode, which can save content when the bitstream is slightly corrupted:

ffmpeg -analyzeduration 200M -probesize 200M -i "broken.mp4" -map 0:v:0? -map 0:a:0? -c:v libx264 -preset veryfast -crf 18 -c:a aac -b:a 192k -fflags +genpts "repaired_reencode.mp4"

To do many files in one go, make a destination folder first, then run this loop from a prompt. Adjust the source path to where your recovered clips live:

for %f in ("C:\Recovered\*.mp4") do C:\Tools\ffmpeg\ffmpeg.exe -err_detect ignore_err -analyzeduration 200M -probesize 200M -i "%f" -map 0:v:0? -map 0:a:0? -c copy -fflags +genpts "C:\Recovered\fixed\%~nf.mkv"

If none of the outputs play, copy the first 30 lines of FFmpeg’s console output from one file and tell me exactly what it reports for the video and audio streams. That will show whether the recovery pulled back only fragments or whether we can tweak the command to match what Medal recorded.
Bryce Valdespino 0 Reputation points

2025-11-21T23:25:24.29+00:00

I ran the command and tried to fix it but its not working. I'm not sure what I'm doing wrong.
Francisco Montilla 30,260 Reputation points Independent Advisor

2025-11-22T01:35:12.1366667+00:00

Please do it again but click in the "Command Prompt" tab instead of Powershell. Powershell has a little different syntax so it will be easier via Command Prompt to avoid changing commmands.
Bryce Valdespino 0 Reputation points

2025-11-22T05:10:04.44+00:00

Same thing.
Francisco Montilla 30,260 Reputation points Independent Advisor

2025-11-23T03:43:11.4533333+00:00
The error happens because there is no ffmpeg.exe in that folder, so Command Prompt and PowerShell cannot find the program.

Follow these steps from scratch.

First, get the correct Windows build of FFmpeg. Download a prebuilt 64 bit static build zip. It must contain a bin folder with ffmpeg.exe inside.

Extract it, then move the extracted folder to C:\Tools\ffmpeg. You should have C:\Tools\ffmpeg\bin\ffmpeg.exe along with ffplay.exe and ffprobe.exe.

Open a new Command Prompt. Run these two commands.

cd /d C:\Tools\ffmpeg\bin ffmpeg -hide_banner

You should now see version text. If you still get not recognized, the bin folder does not contain ffmpeg.exe, stop there and tell me.

Put one broken clip in that same bin folder, then do the remux that regenerates timestamps.

ffmpeg -err_detect ignore_err -analyzeduration 200M -probesize 200M -i "broken.mp4" -map 0:v:0? -map 0:a:0? -c copy -fflags +genpts "repaired.mkv"

If repaired.mkv opens but is still blank or stalls, try the gentle re-encode.

ffmpeg -analyzeduration 200M -probesize 200M -i "broken.mp4" -map 0:v:0? -map 0:a:0? -c:v libx264 -preset veryfast -crf 18 -c:a aac -b:a 192k -fflags +genpts "repaired_reencode.mp4"

Small checks that help: In the bin folder run dir /b *.exe to confirm ffmpeg.exe is there. Keep quotes around names that have spaces. Work on copies of the recovered files only.

If anything here does not match what you see, send one screenshot of C:\Tools\ffmpeg\bin so I can point out what to click next.
Bryce Valdespino 0 Reputation points

2025-11-23T19:35:17.11+00:00

I went through the steps and I ran the first two codes you just sent. At first it seems fine but toward the end there's text in purple, yellow, and red and nothing opens.
Francisco Montilla 30,260 Reputation points Independent Advisor

2025-11-24T04:50:22.9133333+00:00
Nice work, you got FFmpeg set up! The purple and red lines mean the file has no MP4 header at all, so FFmpeg cannot open it as an MP4. The best next move is to force FFmpeg to treat the recovered data as a raw H.264 stream and then wrap it into a fresh container.

Open Command Prompt in C:\Tools\ffmpeg\bin and run this exact command on your broken file that is already in that folder.

ffmpeg -hide_banner -f h264 -analyzeduration 200M -probesize 200M -i "broken.mp4" -c:v copy -fflags +genpts "repaired_from_raw.mp4"

If that output plays but looks jumpy or freezes, do a gentle re-encode which can survive minor bitstream damage:

ffmpeg -hide_banner -f h264 -analyzeduration 200M -probesize 200M -i "broken.mp4" -c:v libx264 -preset veryfast -crf 18 -fflags +genpts "repaired_from_raw_reenc.mp4"

If FFmpeg immediately says that it is not a valid H.264 bitstream or no start codes were found, repeat the same two commands but replace -f h264 with -f hevc and change the output names to end in _hevc.mp4. Medal sometimes records HEVC on newer GPUs.

Tell me exactly what FFmpeg prints in the first 20-30 lines after you run the first command. That will confirm whether we have a valid raw stream to rewrap or if the recovery pulled back only fragments, and I will guide you to the next step.
Bryce Valdespino 0 Reputation points

2025-11-24T20:08:41.5633333+00:00

Both of the commands/processes ended with "Conversion failed!"
Francisco Montilla 30,260 Reputation points Independent Advisor

2025-11-25T03:34:44.58+00:00
Great, that output tells me the file has no MP4 header and also does not contain H.264 start codes. With your RTX 4070 there is a good chance Medal recorded in HEVC. The next step is to force FFmpeg to read the recovered data as raw HEVC and then wrap it in a fresh container.

Open Command Prompt in C:\Tools\ffmpeg\bin again and run this exactly:

ffmpeg -hide_banner -f hevc -analyzeduration 200M -probesize 200M -i "broken.mp4" -c:v copy -fflags +genpts "repaired_from_hevc.mp4"

If that runs but the output still will not play, do the gentle re-encode version:

ffmpeg -hide_banner -f hevc -analyzeduration 200M -probesize 200M -i "broken.mp4" -c:v libx265 -preset veryfast -crf 20 -fflags +genpts "repaired_from_hevc_reenc.mp4"

Try those two in that order and tell me what FFmpeg prints for the first command. That will confirm whether the stream really is HEVC and whether we have enough continuous data to salvage.
Bryce Valdespino 0 Reputation points

2025-11-25T18:33:15.25+00:00

Same message. Also, I don't know if it makes a difference but I have an RTX3080.
Francisco Montilla 30,260 Reputation points Independent Advisor

2025-11-26T06:13:14.96+00:00

Your FFmpeg logs show there are no H.264 or HEVC start codes and no codec parameters at all. That means the file you recovered is not a continuous video stream. When that happens, the next move is to redo the recovery with a raw carver that scans the disk for video data instead of trying to resurrect the deleted file entry. Use PhotoRec, which is free and open source.

Do this exactly.

Download TestDisk and PhotoRec for Windows, extract the ZIP, then open photorec_win.exe. Select the physical drive where the clips were originally deleted. Choose the partition that held the clips, then choose Free to scan only unallocated space.

Press File Opt, press s once to clear all types, then enable mp4 and mov. Confirm and return to the main screen. Choose a destination folder on a different drive than the one you are scanning, ideally your larger drive with plenty of free space. Start the scan and let it complete. You will get folders named recup_dir.1, recup_dir.2, and so on containing whatever contiguous video chunks are still present.

When it finishes, try opening the larger recovered mp4 or mov files in VLC. If they do not open or only blink, copy one into C:\Tools\ffmpeg\bin and run the two commands you already tried earlier, first the remux that keeps streams and generates timestamps, then the gentle re encode if needed.

If a file still fails with the same errors, it means the carved piece is only a fragment and does not contain usable start codes. In that case, keep the larger ones you found and we will try another pass that targets different signatures.

One important note: If the original drive is an SSD, Windows sends TRIM when you empty Recycle Bin`. That can wipe the deleted areas quickly. PhotoRec is still worth a full pass, but if it only finds tiny files or outputs mostly zeros, the data has already been erased by the controller and there will be nothing left to rebuild.

Run the PhotoRec pass exactly as above and tell me two things: roughly how many mp4 or mov files it found and the size range of the biggest few. From that I will tell you the fastest next step.
Bryce Valdespino 0 Reputation points

2025-11-28T19:57:00.78+00:00

I downloaded the testdisk/photorec correctly and opened it, and I think I did it right when I selected the disk, partition, and chose free. However, the image below shows the product and I don't know what I'm supposed to do from here so I may have done it wrong.

Share via

Corrupted MP4 Files

2 answers

Your answer