TOPIC:

Using Apple M1-Max, with Ventura - although this fact is not relevant.

I was handed an SD card out of a Sony 4K camcorder with a 45 GB MP4 file. Nothing can read this file, either on Windows, Mac or the original camcorder!

Now it so happens that while I have been digging around on my Mac, I came across 2 instances of the seemingly same smaller (unrelated to the big file) files. One can be opened and viewed, but the other cannot. They have the exact same time stamps and byte lengths. I have uploaded the "bad" version for anyone to try to make readable. Here is the LINK on my Google Drive. (drive.google.com/file/d/1so8ZzTdGMODUfGk...xyx/view?usp=sharing)

NOTE: Please check for virus infection, just in case! It is not an executable, so should be safe.

If you can make it readable, perhaps the same steps will work on the big 45 GB MP4 file.

I have tried, unsuccessfully with all of these:

• FCP X
• DaVinci v18
• Compressor
• HandBrake
• VLC
• Apple Preview
• MediaInfo

Also note that although the byte lengths of the "good" and the "bad" files are the same, the HASH values were DIFFERENT.

Looking forward to a solution!

The file is damaged/empty. I opened it in "Hex Fiend", a binary/hex file editor. Besides a bit of file header info and some gibberish, well over 95% of the file contains zeroes. Here's the beginning of the file:



ftypmp42isomiso2avc1mp41free7K“mdatõÿÿñÜEé½æÙH·–,Ø Ù#îïx264 - core 157 r2935 545de2f - H.264/MPEG-4 AVC codec - Copyleft 2003-2018 - www.videolan.org/x264.html - options: cabac=1 ref=2 deblock=1:0:0 analyse=0x1:0x111 me=hex subme=6 psy=1 psy_rd=1.00:0.00 mixed_ref=1 me_range=16 chroma_me=1 trellis=1 8x8dct=0 cqm=0 deadzone=21,11 fast_pskip=1 chroma_qp_offset=-2 threads=22 lookahead_threads=3 sliced_threads=0 nr=0 decimate=1 interlaced=0 bluray_compat=0 constrained_intra=0 bframes=3 b_pyramid=2 b_adapt=1 b_bias=0 direct=1 weightb=1 open_gop=0 weightp=1 keyint=250 keyint_min=25 scenecut=40 intra_refresh=0 rc_lookahead=30 rc=crf mbtree=1 crf=22.0 qcomp=0.60 qpmin=0 qpmax=69 qpstep=4 vbv_maxrate=20000 vbv_bufsize=25000 crf_max=0.0 nal_hrd=none filler=0 ip_ratio=1.40 aq=1:1.00

Invisor (similar to MediaInfo) opens the file and shows just this:

"File"
"Name","Victor Lines BAD.mp4"
"Size","206 MB (206370815 bytes)"
"Kind","MPEG-4 movie"
"UTI","public.mpeg-4"
"Downloaded From","doc-0c-bs-docs.googleusercontent.com/doc...0ssghhb4bh5rka3emodb, drive.google.com/""Downloaded Date","December 9, 2022 at 06:45:26"

"Container"
"Format","MPEG-4"
"Format profile","Base Media / Version 2"
"Codec ID","mp42 (isom/iso2/avc1/mp41)"

So, it seems that when file was created but something happened to the actual contents or it never contained valid data.

My suggestion is placing it back in the camera that made it and see if it plays. If it plays then capture it real time to an external recorder. Editors will be miffed that any metadata will be lost in the transition but the only remedy for that is to reshoot.... the wedding?

(I've found this type of corruption typically happens if the battery dies during recording. I have 68GB of splendid footage of ZZ Top playing Super Bowl LI that I recovered from just a dead battery occurrence and it looks like one of those trendy glitch Fx that's so vogue these days has heavily soaked the footage.)

Thanks for the analysis. Interesting results. I would love to know how this empty file got created. It has the same name, time stamps and byte length as the good version. Ah well, at least there is no merit in trying to restore it. I will just delete all of the corrupt files.

Thanks again for looking into this.

VTC wrote:

My suggestion is placing it back in the camera that made it and see if it plays. If it plays then capture it real time to an external recorder. Editors will be miffed that any metadata will be lost in the transition but the only remedy for that is to reshoot.... the wedding?

Snip 8<

As I mentioned in my original note, I had already tried that and the camera couldn't open the file either.

Most of the PRO model Sony cameras have a clip repair function somewhere in the menu system. If yours does and you haven't tried it, you might see if it helps.

Unfortunately, the camera didn't have this feature. Luckily we were using 4 cameras, so losing one was not catastrophic.

have you tried the recovery tool PHOTOREC?
It once saved my *** , and recovered files which survived 5 (five!) times formatting the card.
A bit tricky in use - a Terminal app…

PHOTOREC seems to be only for Intel Macs, but mine is an M1 mac.

pszilard wrote:

PHOTOREC seems to be only for Intel Macs, but mine is an M1 mac.

Normally an Intel MacOS app will run on Apple Silicon. There might be some cases where the app is very old or requires specialized I/O where it won't run, but all Intel MacOS apps I've tried will run on Apple Silicon.