problem: sound only, no pictue?

[BryceS]

Hi,

When I open one of our mp4 files taken from a hdmi capture card via ffmpeg we get the sound only, there is no picture displayed.

Background:
We have been using Smart Cutter for years to edit the output of our hauppauge recordings, setting start and end.
Due to hardware issues we are now moving to a 'blackmagic design intensity pro 4k' taking input from an hdmi cable.

This stream is run through ffmpeg to generate a mp4 file.
ffmpeg setting used are:

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  ffmpeg <InputStuff>   -c:v h264 -vf  "yadif=0:-1:0"  -pix_fmt yuv422p  -crf 23  output.mp4
              ( video codec h264;    deinterlace;       colour space;    constant rate factor ) 

Problem:
When I open this file in Smart Cutter the program crashes, so I moved to MovieShop Framer where it opens but only plays the audio.
This movie plays fine in vlc player which says it is:

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Stream 0
     Type: Video
     Codec: H264 - MPEG-4 AVC (part 10)(avc1)
     Resolution: 1920X1090
     Display resolution: 1920X1080
     Frame rate: 25
     Decoded format: Planar 4:2:2 YUV
  Stream 1 .... all the audio stuff. 

When opened in Framer it says:

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  Fmt : Quicktime/MOV
  Video : h264decoder
  Dim : 1920X1074
  Audio : faad 

So this info seems to disagree a bit maybe, resolutions especially? I don't know enough on this topic to know what to expect.

Does anyone have any idea where I may have gone wrong please?

Thanks,
Bryce Stenberg.

[admin]

Dear Bryce:
Thanks for your message.

'When I open one of our mp4 files taken from a hdmi capture card via ffmpeg we get the sound only, there is no picture displayed.'
Please help us to show and identify the problem.

Could you please upload a original video sample showing the problem to our ftp server for a test?
We want not only the ffmpeg generated mp4 file but also the very original source mp4 file from your hdmi capture.

It would be better if the sample file size is less than 50 MB.

-------------------------------------
before uploading sample, please create sub-directory with your name under the root, then upload sample to this sub-directory.

FULL priviliged --- mkdir, read, write, remove
Will be helpful to limit the sample file size under 50MB.
Thank you.

FTP Username: samples@fame-ring.com
Password: samples
FTP Server: ftp.fame-ring.com
FTP Server Port: 21
-------------------------------------
Here is also a step by step tutorial for uploading sample(s):
http://www.fame-ring.com/uphelp.html

Looking forward to your further message.
Thank you very much.

Best Regards,
FameRing Support Team

[BryceS]

Thanks team,

I'll create a smaller file tonight and send it tomorrow.
There is only the one file generated by ffmpeg, it is taking its input direct from the hdmi stream coming out of a sky box so there is no file on the input side of things to compare to.

Regards, Bryce.

[BryceS]

Hi team,

I have now uploaded a file at /BryceS/Test01.mp4 with size of 24.3MB.
I look forward to your response

Regards, Bryce.

[admin]

Dear Bryce:
Thanks for your message and the sample file.

We did re-produce the issue on our end.
On the other hand, we found that Quick Time Player does not recognize this sample file either. The sample file seems to be an invalid mp4/mov video. The underlying reason could be the container meta data describing the video resolution.

We will investigate the sample for more info. Will keep you posted about the progress.

Please feel free to send us your further advice and suggestion.
Thank you very much.

Best Regards,
FameRing Support Team

[BryceS]

Hi Team,

To give a complete picture in case it helps, the input side to ffmpeg program is hdmi cable into 'Blackmagic Design Intensity Pro 4K' running 1920X1080 at 25000/1000fps (interlaced, upper field first) using decklink.
So whole command I run is:

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  ffmpeg  -f decklink -i "Intensity Pro 4K@8" -c:v h264 -vf  "yadif=0:-1:0"  -pix_fmt yuv422p  -crf 23  output.mp4

I can get hold of the recording machine again on Monday so I will try varying the ffmpeg parameters then to see if something comes right.
I downloaded a couple of mp4 metadata readers, and see for my test file one says 'video type: invalid' while other appeared to indicate the right resolution for the video track. Then again, it also showed a lot in the header, the readable stuff said:

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H.264/MPEG-4 AVC codec - Copyleft 2003-2015 - http://www.videolan.org/x264.html - options: cabac=1 ref=3 deblock=1:0:0: analyse=0x3:0x113 me=hex subme=7 psy=1 psy_rd=1.00:0.00 mixed_ref=1 me_range=16 chroma_me=1 trellis=1 8x8dct=1 cqm=0 deadzone=21,11 fast_pskip=1 chroma_qp_offset=-2 threads=12 lookahead_threads=2 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=2 keyint=250 keyint_min=25 scenecut=40 intra_refresh=0 rc_lookahead=40 rc=crf mbtree=1 crf=23.0 qcomp=0.60 qpmin=0 qpmax=69 qpstep=4 ip_ratio=1.40 aq=1:1.00

but I'm a complete novice at this - don't know what should look right or not in here. I tried comparing the header against a file from the previous system that has been run through smart cutter, but the programs couldn't open it, error 'invalid atom size'. I'll try to get hold of an original mp4 from previous system and compare the headers in case of any further clues.

I'll also post on an ffmpeg forum and see if anyone there may have advice.
Hopefully we can get to the bottom of this and can help others with this posting.

Regards,
Bryce.

[BryceS]

Hi,

I managed to get hold of the gear again, played around some more with the settings.

Looking at one of our .ts files generated from the hauppauge card using VLC I noticed that it said 'Decoded format: Planar 4:2:0 YUV' (maybe this is how it comes from tuner and can't be set higher?)

Anyway, guessing this is something to do with the colourspace parameter which I had used 'yuv422p' in ffmpeg I changed it to be 'yuv420p', and voila - can now see the picture in framer for editing.

so final working line is:

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ffmpeg <InputStuff>   -c:v h264 -vf  "yadif=0:-1:0"  -pix_fmt yuv420p  -crf 23  output.mp4

Should that have meant the Framer program should have broken on it, I don't know?
I don't understand why what I just did works, if someone could elaborate that would be nice

Regards, Bryce.

[admin]

Dear Bryce:
Thanks for your message.

'something to do with the colourspace parameter which I had used 'yuv422p' in ffmpeg I changed it to be 'yuv420p', and voila - can now see the picture in framer for editing.'
Nice, glad to hear that!

Please feel free to send us your further advice and suggestion.
Thank you very much.

Best Regards,
FameRing Support Team

[BryceS]

Hi,

Just a quick follow up message for anyone coming across this thread, in case it helps.

After I had the video and audio working properly I found it was not able to be edited in SmartCutter - this program would keep crashing ( ) when trying to position new start and end points.

The fix was to add more Iframes (index key frames) to the recording via ffmpeg with parameters:
-x264opts keyint=12:min-keyint=8
I think this said to give me an IFrame every 8 frames. It didn't make the file much larger either, at least on my subject matter.

So the whole line now looks like:

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ffmpeg <InputStuff>   -c:v libx264  -vf  "yadif=0:-1:0"  -pix_fmt yuv420p  -crf 23  -x264opts keyint=12:min-keyint=8    output.mp4

Regards,
Bryce.