[FFmpeg-user] Trying to extract video stream but output only has 30 frames

[William Breathitt Gray]

On Sat, Apr 10, 2021 at 01:54:45PM +0100, Rob Hallam wrote:
> On Sat, 10 Apr 2021 at 13:43, William Breathitt Gray
> <vilhelm.gray at gmail.com> wrote:
> 
> > $ ffprobe VID_20210401_150222.mp4 -hide_banner
> > ...
> >     com.android.version: 11
> 
> This looks like it's been created on a mobile device. I have had
> experience of a phone creating a 'truncated' file which cut off
> before the actual due to a corrupt MOOV atom / extraneous 'ftyp'
> atoms.
> 
> The video file played correctly on the phone and on online viewers (eg
> YT) but not with either VLC, ffplay, etc.

Yes, that essentially my situation (recorded video on phone, but file
seems to have been generated with a fault -- perhaps due to truncation
as your mention), I can play the video file correctly on my phone and
desktop (albeit with some minor corrupted video frames and perhaps an
audio skip here or there), but when I try to convert the video file
using ffmpeg, I am unable to generate a useful output. I could perhaps
use another tool, but I'd like to understand where I'm going wrong with
ffmpeg because I do believe it is capable of doing what I want if I
learn how it works.

> 
> I could salvage the file by uploading to eg GDocs / YouTube and
> re-downloading. You may also wish to have a look at the fork of
> untrunc. Others here can advise if ffmpeg can do something useful
> with your video file.
> 
> > $ ffmpeg -hide_banner -i VID_20210401_150222.mp4 -c:v copy -an onlyvideo.mp4
> 
> Separately, I have seen others advise not to use -hide_banner when
> preparing output for questions asked of this list. It is germane to know
> what version a querent is using and with which options.
> 
> Cheers,
> Rob

Ah yes that makes sense, I'll make sure to include the banner in my
future responses then.

Thank you,

William Breathitt Gray
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