Fwd: OBS and OBS Portable Recording Into Same File Simultaneously

classic Classic list List threaded Threaded
8 messages Options
Reply | Threaded
Open this post in threaded view
|

Fwd: OBS and OBS Portable Recording Into Same File Simultaneously

David Bayles
Corrupted video file, FFprobe output text file, and FFmpeg output text file
are all available to download here:
https://drive.google.com/drive/folders/1R0Y5plgkhTWWFNNKgSNJ5yitpKQbIKgg?usp=sharing

I'm hoping there is a way to extract good video and audio from this video
file, this was for a very important job that is impossible to do again. The
video linked is a 1 minute recreation of the exact same problem... the
actual video file is confidential (for a legal court case) and is much
longer/larger. I used the exact same settings, the only difference was the
window OBS was capturing (I used a YouTube video as opposed to the
videoconference software window used for the deposition).

Here's what happened:

In OBS and OBS Portable, my video technician had the save location set to
the same exact folder (this was not how I intended it to be, but he made a
last minute change to accomadate what he suspected was a faulty hard
drive). We also had a hotkey to start recording on both apps
simultaneously. We left the auto naming scheme in place for both instances
of OBS since they were supposed to be saving to two totally different
external hard drives (we have since changed this). This perfect storm
resulted in both recordings being written into a single file (see link
above), instead of two files as intended. It is unplayabe in VLC.

I ran an FFprobe (available via link above), and found that there are 8
streams in the file. Each file should have had 4 streams (1 video and 3
audio streams per my setup in OBS), so at first glance it looks like all
the data is there in some form/arrangement.

I tried to map the 0:0 stream to a new file and tried the same thing with
the 0:4 stream (these are the video streams), but did not have any luck
extracting good video. Here are the two things I ran (again see link above
for text files with full FFmpeg ouput of each):

ffmpeg -i C:\Users\David\Videos\2020-06-23_17-39-32_corrupted.mkv -map 0:0
-c copy C:\Users\David\Videos\2020-06-23_17-39-32_corrupted_map0-0.mkv

ffmpeg -i C:\Users\David\Videos\2020-06-23_17-39-32_corrupted.mkv -map
0:4 -c copy C:\Users\David\Videos\2020-06-23_17-39-32_corrupted_map0-4.mkv

It seems the audio is intact, as I was able to map one of the audio streams
into a wav file... although there seemed to be extra/repeated audio tacked
onto where the video/audio should have ended...

It looks to me like both video streams got written into stream 0:0, while
stream 0:4 looks empty (because this map results in a very small file).
However the thing that's weird (and maybe promising) is that when I play
the corrupted file in VLC, it mostly looks like smeared digital colors, but
if I click around to different times in the video, it sometimes shows good
video.

My life would saved if there is a way to extract good video/audio from this
corrupted file. Any help would be greatly appreciated, thanks in advance!
_______________________________________________
ffmpeg-user mailing list
[hidden email]
https://ffmpeg.org/mailman/listinfo/ffmpeg-user

To unsubscribe, visit link above, or email
[hidden email] with subject "unsubscribe".
Reply | Threaded
Open this post in threaded view
|

Re: Fwd: OBS and OBS Portable Recording Into Same File Simultaneously

FFmpeg-users mailing list
David Bayles <[hidden email]> writes:

> Corrupted video file, FFprobe output text file, and FFmpeg output text file
> are all available to download here:
> https://drive.google.com/drive/folders/1R0Y5plgkhTWWFNNKgSNJ5yitpKQbIKgg?usp=sharing
>
> I'm hoping there is a way to extract good video and audio from this video
> file, this was for a very important job that is impossible to do again. The
> video linked is a 1 minute recreation of the exact same problem... the
> actual video file is confidential (for a legal court case) and is much
> longer/larger. I used the exact same settings, the only difference was the
> window OBS was capturing (I used a YouTube video as opposed to the
> videoconference software window used for the deposition).

I am no expert, but for the video, I would try using the select filter
to capture the I-frames.

https://ffmpeg.org/ffmpeg-all.html#toc-select_002c-aselect

See the 4th example in the examples section.

Leo
_______________________________________________
ffmpeg-user mailing list
[hidden email]
https://ffmpeg.org/mailman/listinfo/ffmpeg-user

To unsubscribe, visit link above, or email
[hidden email] with subject "unsubscribe".
Reply | Threaded
Open this post in threaded view
|

Re: Fwd: OBS and OBS Portable Recording Into Same File Simultaneously

David Bayles
Trying this now! Thanks!

On Thu, Jun 25, 2020 at 11:03 PM Leo Butler via ffmpeg-user <
[hidden email]> wrote:

> David Bayles <[hidden email]> writes:
>
> > Corrupted video file, FFprobe output text file, and FFmpeg output text
> file
> > are all available to download here:
> >
> https://drive.google.com/drive/folders/1R0Y5plgkhTWWFNNKgSNJ5yitpKQbIKgg?usp=sharing
> >
> > I'm hoping there is a way to extract good video and audio from this video
> > file, this was for a very important job that is impossible to do again.
> The
> > video linked is a 1 minute recreation of the exact same problem... the
> > actual video file is confidential (for a legal court case) and is much
> > longer/larger. I used the exact same settings, the only difference was
> the
> > window OBS was capturing (I used a YouTube video as opposed to the
> > videoconference software window used for the deposition).
>
> I am no expert, but for the video, I would try using the select filter
> to capture the I-frames.
>
> https://ffmpeg.org/ffmpeg-all.html#toc-select_002c-aselect
>
> See the 4th example in the examples section.
>
> Leo
> _______________________________________________
> ffmpeg-user mailing list
> [hidden email]
> https://ffmpeg.org/mailman/listinfo/ffmpeg-user
>
> To unsubscribe, visit link above, or email
> [hidden email] with subject "unsubscribe".
_______________________________________________
ffmpeg-user mailing list
[hidden email]
https://ffmpeg.org/mailman/listinfo/ffmpeg-user

To unsubscribe, visit link above, or email
[hidden email] with subject "unsubscribe".
Reply | Threaded
Open this post in threaded view
|

Re: Fwd: OBS and OBS Portable Recording Into Same File Simultaneously

David Bayles
I tried this:
C:\Users\David>ffmpeg -i "C:\Users\David\Downloads\2020-06-23 09-02-44
corrupt.mkv" -vf select='eq(pict_type\,I)'
"C:\Users\David\Downloads\2020-06-23 09-02-44 corrupt SELECT I-FRAMES.mkv"
2> "C:\Users\David\Downloads\2020-06-23 09-02-44 corrupt SELECT
I-FRAMES.txt"

And got this (video and log file):
https://drive.google.com/drive/folders/1OMf6oeLIkYU1d05dPqO1tfOxI1_KnYGK?usp=sharing

Is that what you meant to do? Any other ideas?

Thanks!

On Thu, Jun 25, 2020 at 11:43 PM David Bayles <[hidden email]> wrote:

> Trying this now! Thanks!
>
> On Thu, Jun 25, 2020 at 11:03 PM Leo Butler via ffmpeg-user <
> [hidden email]> wrote:
>
>> David Bayles <[hidden email]> writes:
>>
>> > Corrupted video file, FFprobe output text file, and FFmpeg output text
>> file
>> > are all available to download here:
>> >
>> https://drive.google.com/drive/folders/1R0Y5plgkhTWWFNNKgSNJ5yitpKQbIKgg?usp=sharing
>> >
>> > I'm hoping there is a way to extract good video and audio from this
>> video
>> > file, this was for a very important job that is impossible to do again.
>> The
>> > video linked is a 1 minute recreation of the exact same problem... the
>> > actual video file is confidential (for a legal court case) and is much
>> > longer/larger. I used the exact same settings, the only difference was
>> the
>> > window OBS was capturing (I used a YouTube video as opposed to the
>> > videoconference software window used for the deposition).
>>
>> I am no expert, but for the video, I would try using the select filter
>> to capture the I-frames.
>>
>> https://ffmpeg.org/ffmpeg-all.html#toc-select_002c-aselect
>>
>> See the 4th example in the examples section.
>>
>> Leo
>> _______________________________________________
>> ffmpeg-user mailing list
>> [hidden email]
>> https://ffmpeg.org/mailman/listinfo/ffmpeg-user
>>
>> To unsubscribe, visit link above, or email
>> [hidden email] with subject "unsubscribe".
>
>
_______________________________________________
ffmpeg-user mailing list
[hidden email]
https://ffmpeg.org/mailman/listinfo/ffmpeg-user

To unsubscribe, visit link above, or email
[hidden email] with subject "unsubscribe".
Reply | Threaded
Open this post in threaded view
|

Re: Fwd: OBS and OBS Portable Recording Into Same File Simultaneously

David Bayles
Perhaps another question: if I extract each and every frame as an image
file, then go through one by one and there is no still image resembling
what I filmed (i.e. every frame/picture is just solid green), does that
mean that the video is definitely unrecoverable? Or might there be another
way to recover the video?



On Fri, Jun 26, 2020 at 12:32 AM David Bayles <[hidden email]> wrote:

> I tried this:
> C:\Users\David>ffmpeg -i "C:\Users\David\Downloads\2020-06-23 09-02-44
> corrupt.mkv" -vf select='eq(pict_type\,I)'
> "C:\Users\David\Downloads\2020-06-23 09-02-44 corrupt SELECT I-FRAMES.mkv"
> 2> "C:\Users\David\Downloads\2020-06-23 09-02-44 corrupt SELECT
> I-FRAMES.txt"
>
> And got this (video and log file):
>
> https://drive.google.com/drive/folders/1OMf6oeLIkYU1d05dPqO1tfOxI1_KnYGK?usp=sharing
>
> Is that what you meant to do? Any other ideas?
>
> Thanks!
>
> On Thu, Jun 25, 2020 at 11:43 PM David Bayles <[hidden email]>
> wrote:
>
>> Trying this now! Thanks!
>>
>> On Thu, Jun 25, 2020 at 11:03 PM Leo Butler via ffmpeg-user <
>> [hidden email]> wrote:
>>
>>> David Bayles <[hidden email]> writes:
>>>
>>> > Corrupted video file, FFprobe output text file, and FFmpeg output text
>>> file
>>> > are all available to download here:
>>> >
>>> https://drive.google.com/drive/folders/1R0Y5plgkhTWWFNNKgSNJ5yitpKQbIKgg?usp=sharing
>>> >
>>> > I'm hoping there is a way to extract good video and audio from this
>>> video
>>> > file, this was for a very important job that is impossible to do
>>> again. The
>>> > video linked is a 1 minute recreation of the exact same problem... the
>>> > actual video file is confidential (for a legal court case) and is much
>>> > longer/larger. I used the exact same settings, the only difference was
>>> the
>>> > window OBS was capturing (I used a YouTube video as opposed to the
>>> > videoconference software window used for the deposition).
>>>
>>> I am no expert, but for the video, I would try using the select filter
>>> to capture the I-frames.
>>>
>>> https://ffmpeg.org/ffmpeg-all.html#toc-select_002c-aselect
>>>
>>> See the 4th example in the examples section.
>>>
>>> Leo
>>> _______________________________________________
>>> ffmpeg-user mailing list
>>> [hidden email]
>>> https://ffmpeg.org/mailman/listinfo/ffmpeg-user
>>>
>>> To unsubscribe, visit link above, or email
>>> [hidden email] with subject "unsubscribe".
>>
>>
_______________________________________________
ffmpeg-user mailing list
[hidden email]
https://ffmpeg.org/mailman/listinfo/ffmpeg-user

To unsubscribe, visit link above, or email
[hidden email] with subject "unsubscribe".
Reply | Threaded
Open this post in threaded view
|

Re: Fwd: OBS and OBS Portable Recording Into Same File Simultaneously

Moritz Barsnick
In reply to this post by David Bayles
On Wed, Jun 24, 2020 at 10:59:51 -0400, David Bayles wrote:
> In OBS and OBS Portable, my video technician had the save location set to
> the same exact folder (this was not how I intended it to be, but he made a
> last minute change to accomadate what he suspected was a faulty hard
> drive). We also had a hotkey to start recording on both apps
> simultaneously. We left the auto naming scheme in place for both instances
> of OBS since they were supposed to be saving to two totally different
> external hard drives (we have since changed this). This perfect storm
> resulted in both recordings being written into a single file (see link
> above), instead of two files as intended. It is unplayabe in VLC.

Assuming that both programs appended to the file (and didn't overwrite
each other at the same file position), you would have double the data,
interleaved on operating system / file system level.

To properly disassemble at least one of the two halves, you would
probably need to operate of block level, understanding how large the
blocks were, and trying to fiddle out the ones from the one program and
the ones from the other, while making sense to a decoder.

I consider that ffmpeg gives you some results at all a coincidence - it
could just as well we confused at the first inconsistency. (I assume
Matroska allows for some of this recovery.

I do understand that you would like to use ffmpeg to re-assemble the
original video, especially as extracting audio looks somehwat
promising. Yet the video's block sizes will not correspond to the file
system's block sizes, and ffmpeg will keep encountering inconcistencies
to the point of giving up, unless you take away the conflicting
segments.

> My life would saved if there is a way to extract good video/audio from this
> corrupted file. Any help would be greatly appreciated, thanks in advance!

You could try to observe at which point ffmpeg detects the first errors
(the showinfo filter will indicate the byte position ffmpeg is
operating on), and from there remove blocks of 512, 1024, 2048 bytes,
hoping that after removal of some of them, you hit a proper block
again, and ffmpeg will no longer "lose sync" at that point, until again
a later point in the file.

Just a wild suggestion.

Oh, and if the two OBS overwrote each other's data, I'm pretty sure
you're lost.

Cheers,
Moritz
_______________________________________________
ffmpeg-user mailing list
[hidden email]
https://ffmpeg.org/mailman/listinfo/ffmpeg-user

To unsubscribe, visit link above, or email
[hidden email] with subject "unsubscribe".
Reply | Threaded
Open this post in threaded view
|

Re: Fwd: OBS and OBS Portable Recording Into Same File Simultaneously

Gyan Doshi-2


On 26-06-2020 02:08 pm, Moritz Barsnick wrote:
> You could try to observe at which point ffmpeg detects the first errors
> (the showinfo filter will indicate the byte position ffmpeg is
> operating on), and from there remove blocks of 512, 1024, 2048 bytes,
> hoping that after removal of some of them, you hit a proper block
> again, and ffmpeg will no longer "lose sync" at that point, until again
> a later point in the file.

showinfo operates upon decoded frames. This inspection will have to be
done at the container level using a forensic tool which can identify
start and end of block structures in Matroska. This assumes that the two
write operations didn't write on top of each other. One saving grace
could be that OBS, like ffmpeg, flushes data to files in blocks of 256
kB, although I don't know if this is the case.

Gyan


_______________________________________________
ffmpeg-user mailing list
[hidden email]
https://ffmpeg.org/mailman/listinfo/ffmpeg-user

To unsubscribe, visit link above, or email
[hidden email] with subject "unsubscribe".
Reply | Threaded
Open this post in threaded view
|

Re: Fwd: OBS and OBS Portable Recording Into Same File Simultaneously

David Bayles
> showinfo operates upon decoded frames. This inspection will have to be
> done at the container level using a forensic tool which can identify
> start and end of block structures in Matroska.

Can you suggest a forensic tool or even a company/person that could help me recover this? I’d be willing to pay for this service/tool.

On Fri, Jun 26, 2020 at 5:23 AM Gyan Doshi <[hidden email]> wrote:

>
>
> On 26-06-2020 02:08 pm, Moritz Barsnick wrote:
> > You could try to observe at which point ffmpeg detects the first errors
> > (the showinfo filter will indicate the byte position ffmpeg is
> > operating on), and from there remove blocks of 512, 1024, 2048 bytes,
> > hoping that after removal of some of them, you hit a proper block
> > again, and ffmpeg will no longer "lose sync" at that point, until again
> > a later point in the file.
>
> showinfo operates upon decoded frames. This inspection will have to be
> done at the container level using a forensic tool which can identify
> start and end of block structures in Matroska. This assumes that the two
> write operations didn't write on top of each other. One saving grace
> could be that OBS, like ffmpeg, flushes data to files in blocks of 256
> kB, although I don't know if this is the case.
>
> Gyan
>
>
> _______________________________________________
> ffmpeg-user mailing list
> [hidden email]
> https://ffmpeg.org/mailman/listinfo/ffmpeg-user
>
> To unsubscribe, visit link above, or email
> [hidden email] with subject "unsubscribe".
_______________________________________________
ffmpeg-user mailing list
[hidden email]
https://ffmpeg.org/mailman/listinfo/ffmpeg-user

To unsubscribe, visit link above, or email
[hidden email] with subject "unsubscribe".