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• what codec to specify to accessing my HDMI-to-USB adaptor, under Linux ? [closed]

  14 mai 2022, par David

  A week or so ago,I bought a HDMI-to-USB adapter, to use to capture video
TV content from my TV's set-top box. (Xfinity, if it matters. Box generically is :
"XiD X1"...I have both the Pace and the Cisco models available here in this house.)

  


  Specifically, here's the adapter I bought,from Amazon :
https://www.amazon.com/gp/product/B09FLN63B3

  


  So, I'm fluent in both Windows (Win-11) and Linux (Debian 'Bullseye', on my chromebook).

  


  The adapter does not come with any recommendations for what software/drivers to (try to) use, but I was prepared for that.
After some google searches, I decided to first try using the cmd-line
'ffmpeg' program, because I'm
quite familiar with that (excellent !) piece of open-source software !

  


  So, after a day or two of (mostly) success recordings under Win-11, using
ffmpeg's Microsoft-based 'dshow' (aka 'DirectShow'), I decided to attempt to get
up to the same level of accomplishment on my Chromebook, under Linux, also
using 'ffmpeg'.

  


  [Ok...a very brief explanation of 'mostly' successful. I'll
post another separate question here, about the specifics of my glitches,
using 'dshow' on Windows. But, essentially, when I try to record to a MP4
file, I get 2 scenarios of glitch : #1 : Suddenly, dropped packets surges up,
and I get "1000 dropped' yellow msg #2 : On other trials, I get '...contains
no image...'.) So, I figured I should first give a Linux a chance,
before spending more effort trying to resolve the glitches on Windows.]

  


  My first snag, was learning that 'dshow' seems to be specific to 'Windows',
and thus ffmpeg is getting 'unknown' for my reference to 'dshow'. After more hours of 'guessing', I've finally learned/concluded that there are other things
(something call "DeckLink" is one such alternative ?) for Linux, but I'm unclear
what extra Linux packages might exist for ffmpeg support, or whether I will need to built a more complete 'ffmpeg' (e.g. from source code), to get things going under Linux ?

  


  Is my device able to be accessed from some tools other than 'ffmpeg' ?
(e.g. VLC or Handbrake or whatever ?) more easily, on the Linux platform ?

  


  [If I had to, I'd probably invest another $20-$50 in some other hardware
device that goes from HDMI-to-USB (USB-A/B), if it were ]

  


  All ideas are welcome...(TIA)

  


  — Dave

  


• FFMPEG : How to mix different types of image sequence inputs when creating multiple streams

  9 août 2021, par chutlies

  I am using a piece of software that generates a .txt files with rendered images. The list within that txt files is printed with the word 'file' at the beginning of the file path.

  


  Ex : file 'file:C :/Users/User/Desktop/test/Test.0001.png'

  


  I am attempting to input another image sequence as an overlay. Everything works fine if I just overlay, scale, and render. So this works fine :

  


  ffmpeg -hide_banner -y -f concat -safe 0 -i C:/test/input.txt -i "C:/test/BALL.%04d.png" -filter_complex "overlay[4K_in];[4K_in]scale=1920:1080[hdOut]" -map [hdOut] hd.mp4


  


  But when I start to split the stream to create different outputs it will only render the overlayed stream [1:v] and not the composited image.

  


  ffmpeg -hide_banner -y -f concat -safe 0 -i C:/test/input.txt -i "C:/test/BALL.%04d.png" -filter_complex "overlay,split=3[mp4HD_in][mxf720_in][mov4K_in];[mp4HD_in]scale=1920:1080[mp4HD_out];[mxf720_in]scale=1280:720[mxf720_out];[mov4K_in]scale=3840:2160[mov4K_out]" -crf 16 -vcodec libx264 -map [mp4HD_out] C:/test/hdMP4.mp4 -vcodec prores -map [mov4K_out] C:/test/MOV4K.mov -vcodec dnxhd -pix_fmt yuv422p -b:v 75M -map [mxf720_out] C:test/MXF720.mxf


  


  If I remove 'file' from the frames file path in the .txt file it works.

  


  Ex : file 'C :/Users/User/Desktop/test/Test.0001.png'

  


  Unfortunately, I am unable to change this as it's being generated and run within a piece of software. Are there any flags or something that I need to add to get around this ? Any other possible techniques beyond starting another &&ffmpeg call to generate the streams over the overlay ?

  


  I do get this in the logs :&#xA;[concat @ 0000024a0eacf280] DTS -230584300921369 < 0 out of order&#xA;DTS -230584300921369, next:40000 st:0 invalid dropping&#xA;PTS -230584300921369, next:40000 invalid dropping st:0&#xA;DTS -230584300921369, next:40000 st:0 invalid dropping&#xA;PTS -230584300921369, next:40000 invalid dropping st:0&#xA;DTS -230584300921369, next:40000 st:0 invalid dropping&#xA;PTS -230584300921369, next:40000 invalid dropping st:0&#xA;DTS -230584300921369, next:40000 st:0 invalid dropping&#xA;PTS -230584300921369, next:40000 invalid dropping st:0&#xA;[image2 @ 0000024a0eadd140] Thread message queue blocking ; consider raising the thread_queue_size option (current value : 8)

  &#xA;

• FFMPEG : Extract Audio with exact Timing despite corrupted intermediate audio chunks

  5 novembre 2020, par user2029101

  I have a full automated tool chain which first concatenate video chunks and adjusts user events to it.&#xA;This first step uses 3rd party software, I am not able to fix the problem there.&#xA;Later in the process I extract the audio from the video. Sometimes there are corrupted audio chunks inbetween. FFMPEG ignores the corrupted parts on extraction. So I got a mutch shorter audio (the linked events rely on the exact length of the org A/V). It wouldnt be a big issue if it would only happen at the end, I know how to pad it there, but at random poistions, I didnt find an option at the documentation doing the job.&#xA;The only solution that worked was (pretty dirty I know) to convert the video to another video container with removed video stream and rename the file to MP3/AAC. It was working at windows/Android but all Mac-Browser didnt play it.

  &#xA;

  The -filter_complex -discard looks promising but I didnt find any good example for the correct syntax.&#xA;I have found an Adobe Tool doing the job correctly so I hope there is a way to do with ffmpeg, too.

  &#xA;

  General
Complete name                  : C:\tmp123\video.mp4
Format                         : MPEG-4
Format profile                 : Base Media
Codec ID                       : isom (isom/iso2/avc1/mp41)
File size                      : 57.8 MiB
Duration                       : 6 min 51 s
Overall bit rate               : 1 177 kb/s
Writing application            : Lavf58.26.100

Video
ID                             : 1
Format                         : AVC
Format/Info                    : Advanced Video Codec
Format profile                 : Baseline@L4
Format settings, CABAC         : No
Format settings, RefFrames     : 2 frames
Format settings, GOP           : M=1, N=30
Codec ID                       : avc1
Codec ID/Info                  : Advanced Video Coding
Duration                       : 6 min 51 s
Bit rate                       : 1 003 kb/s
Width                          : 1 920 pixels
Height                         : 1 080 pixels
Display aspect ratio           : 16:9
Frame rate mode                : Constant
Frame rate                     : 30.303 FPS
Color space                    : YUV
Chroma subsampling             : 4:2:0
Bit depth                      : 8 bits
Scan type                      : Progressive
Bits/(Pixel*Frame)             : 0.016
Stream size                    : 49.2 MiB (85%)

Audio
ID                             : 2
Format                         : AAC
Format/Info                    : Advanced Audio Codec
Format profile                 : LC
Codec ID                       : 40
Duration                       : 6 min 51 s
Bit rate mode                  : Constant
Bit rate                       : 168 kb/s
Channel(s)                     : 2 channels
Channel positions              : Front: L R
Sampling rate                  : 44.1 kHz
Frame rate                     : 43.066 FPS (1024 SPF)
Compression mode               : Lossy
Stream size                    : 8.22 MiB (14%)
Default                        : Yes
Alternate group                : 1


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