Black blank frames for most of a video

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Level 1

4 points

Black blank frames for most of a video

I'm trying to load in an H.264 .MP4 video from a dashcam, but I'm having playback issues in FCP X.

Basically I see mostly black frames, but every 1/2 a sec (after 15 frames of a 30 fps video), I get one frame of video before it goes black again.

In Quicktime I see something similar where it updates the video once every half sec, but it otherwise keeps the previous frame on screen so at least I can keep seeing some video.

In VLC the video plays back normally at 30 fps.

I've tried resetting my FinalCut preferences, but no luck. Lots of other videos play fine in FCP, including video footage from other dashcams. Any ideas on what I can do to get the video file to play back properly?

I'm running FCP X 10.6.5 and MacOS Ventura.

Thanks!

Posted on Nov 10, 2022 2:06 PM

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Answer 1

Top-ranking reply

terryb

Level 4

3,394 points

Nov 10, 2022 3:19 PM in response to SKPhoton

Sounds like the dashcam is creating non-standard mp4 files that are confusing QT and FCP.

Transcoding with Handbrake might fix it.

Or transcoding in ffmpeg.

$ ffmpeg -i badfile.mp4 output.mp4

Or Compressor if you have it.

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Answer 2

Alchroma

Level 7

23,918 points

Nov 10, 2022 3:04 PM in response to SKPhoton

Using the Finder, right click the video file to call up Encode Selected Video Files.

Select ProRes from the options.

Try using a proRes files once it is completed.

FYI: You will see a small COG icon at the top of your screen, Click it, to reveal a basic progress indicator.

Al

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Answer 3

terryb

Level 4

3,394 points

Nov 10, 2022 4:19 PM in response to SKPhoton

If you've got ffmpeg working, just run it in the directory where your dashcam mp4s are, or copy them into a new folder and work in there just in case there's a problem.

$ for i in *.mp4; do ffmpeg -i "$i" "$i"-transcoded.mp4; done

This will transcode them all to <original name>-transcoded.mp4

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Answer 4

Tom Wolsky

Level 10

152,809 points

Nov 10, 2022 3:11 PM in response to SKPhoton

Could you open the dashcam video in MediaInfo or Invisor and post a screenshot of the full report?

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Answer 5

terryb

Level 4

3,394 points

Nov 10, 2022 3:33 PM in response to SKPhoton

Check the bit rate on the transcoded file to make sure it's close to the original, which in your example is about 60 Mbit/s. Also check the frame rate. And of course, visually compare.

I believe you can setup a batch in Handbrake, if that's what you used.

If you used ffmpeg, do a for loop in the Terminal.

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Answer 6

SKPhoton Author

Level 1

4 points

Dec 2, 2022 1:50 AM in response to Matti Haveri

It looks like the manufacturer must have changed something. Sample footage from 2019 loads just fine, but sample footage from recent firmware doesn't.

Regarding ExifTool, here's its output:

File Size                       : 458 MB
File Modification Date/Time     : 2022:12:01 01:46:32-08:00
File Access Date/Time           : 2022:12:01 20:29:41-08:00
File Inode Change Date/Time     : 2022:12:01 21:02:47-08:00
File Permissions                : -rwx------
File Type                       : MP4
File Type Extension             : mp4
MIME Type                       : video/mp4
Major Brand                     : MP4 v2 [ISO 14496-14]
Minor Version                   : 0.0.0
Compatible Brands               : isom, avc1, mp42
Version                         : 19090372
Thumbnail Image                 : (Binary data 11744 bytes, use -b option to extract)
Media Data Size                 : 458198212
Media Data Offset               : 11824
Movie Header Version            : 0
Create Date                     : 2022:12:01 17:46:32
Modify Date                     : 2022:12:01 17:46:32
Time Scale                      : 60000
Duration                        : 0:01:00
Preferred Rate                  : 1
Preferred Volume                : 100.00%
Preview Time                    : 0 s
Preview Duration                : 0 s
Poster Time                     : 0 s
Selection Time                  : 0 s
Selection Duration              : 0 s
Current Time                    : 0 s
Next Track ID                   : 3
Track Header Version            : 0
Track Create Date               : 2022:12:01 17:46:32
Track Modify Date               : 2022:12:01 17:46:32
Track ID                        : 1
Track Duration                  : 0:01:00
Track Layer                     : 0
Track Volume                    : 0.00%
Image Width                     : 3840
Image Height                    : 2160
Graphics Mode                   : srcCopy
Op Color                        : 0 0 0
Compressor ID                   : avc1
Source Image Width              : 3840
Source Image Height             : 2160
X Resolution                    : 72
Y Resolution                    : 72
Compressor Name                 : h264
Bit Depth                       : 24
Video Frame Rate                : 30
Matrix Structure                : 1 0 0 0 1 0 0 0 1
Media Header Version            : 0
Media Create Date               : 2022:12:01 17:46:32
Media Modify Date               : 2022:12:01 17:46:32
Media Time Scale                : 16000
Media Duration                  : 0:01:00
Balance                         : 0
Handler Class                   : Data Handler
Handler Type                    : URL
Handler Description             : DataHandler
Audio Format                    : mp4a
Audio Channels                  : 1
Audio Bits Per Sample           : 16
Audio Sample Rate               : 16000
Warning                         : [minor] The ExtractEmbedded option may find more tags in the media data
Image Size                      : 3840x2160
Megapixels                      : 8.3
Avg Bitrate                     : 61.1 Mbps
Rotation                        : 0

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Answer 7

SKPhoton Author

Level 1

4 points

Nov 10, 2022 3:05 PM in response to Alchroma

Thank you. I just tried that, but it's not quite right. Framerate drops from 30p to 23.98p and playback still stutters. Instead of going black between frames, it just holds the previous frame.

Additionally since I'm looking to dive deep into video quality, I'd rather avoid any conversions in the first place which could reduce quality.

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Answer 8

SKPhoton Author

Level 1

4 points

Nov 10, 2022 3:26 PM in response to terryb

So it looks like that does help and now I can play it back smoothly. Thanks for the suggestion! I've got a lot of video files so this is going to be time-consuming and tedious to modify. Is there any video quality loss when doing transcoding like this?

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Answer 9

SKPhoton Author

Level 1

4 points

Nov 10, 2022 3:54 PM in response to terryb

Ah gotcha. Yeah the new video that ffmpeg created has a bitrate of around 74 Mbit so it should work.

I also have Compressor and that looks much easier to batch lots of videos. I've never really used it before though so I'm watching a video now to learn. :) Any suggestions on how to set it up to transcode the video with minimal changes to the original video quality? I'm not very familiar with all the different codecs and options.

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Answer 10

SKPhoton Author

Level 1

4 points

Dec 1, 2022 8:57 PM in response to SKPhoton

I just noticed that other dash cameras are producing the same effect in FCP. They're also H.264 MP4's. What's weird is that I used to be able to play and edit their video files no problem a year or two ago. Now that's no longer the case. Did something change with FCPX? I guess it's not one specific dashcam after all. I also don't think it's Ventura that's at fault since I've seen similar issues with video files before Ventura.

Maybe different codecs I can install or something? Ideally I'd like to be able to play back and edit video files normally again without having to putz around with transcoding.

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Answer 11

Dec 2, 2022 1:07 AM in response to SKPhoton

Nonstandard dashcam movies seem to produce lots of problems nowadays.

ExifTool author has made many tunings to his app to get the correct info from incorrect or proprietary dashcam metadata from many vendors. For example, a few days ago some user complained that the year in his movies was 4022 but there is now a workaround in exiftool at least for that device.

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Answer 12

SKPhoton Author

Level 1

4 points

Nov 10, 2022 3:16 PM in response to Tom Wolsky

I'd be happy to, but it looks like both of those are paid apps. Before I try that, would media info from VLC or Quicktime be sufficient?

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Black blank frames for most of a video

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