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• avformat/matroskadec : Simplify checks for cook and ATRAC3

  20 avril 2020, par Andreas Rheinhardt

  avformat/matroskadec : Simplify checks for cook and ATRAC3
  Some conditions which don't change and which can therefore be checked
  
  in read_header() were instead rechecked upon parsing each block. This
  
  has been changed.
  Signed-off-by : Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
  

  • [DH] libavformat/matroskadec.c

• I Can't Upload This Video File (mp4) To Twitter

  1er janvier 2024, par Marcelo Augusto

  I tried to upload a video file (mp4) to Twitter but the site complained it couldn't be uploaded. It seems Twitter has some conditions in order to allow a video upload :

  



  File Type: MP4 or MOV
Max Time: 2 minutes and 20 seconds
Minimum Resolution: 32 x 32
Maximum Resolution: 1920 x 1200
Aspect Ratios: 1:2.39 - 2.39:1 range (inclusive)
Maximum Frame rate: 40 fps
Maximum Video Bitrate: 25 Mbps


  



  And here you are the general infos about the video I was trying to upload but Twitter kept saying there was a problem while processing it (the infos I got through mediainfo) :

  



  General
Complete name                            : tmp03.mp4
Format                                   : MPEG-4
Format profile                           : Base Media
Codec ID                                 : isom (isom/iso2/mp41)
File size                                : 6.71 MiB
Duration                                 : 2mn 15s
Overall bit rate mode                    : Constant
Overall bit rate                         : 417 Kbps
Encoded date                             : UTC 1904-01-01 00:00:00
Tagged date                              : UTC 1904-01-01 00:00:00
Writing application                      : Lavf58.29.100

Video
ID                                       : 1
Format                                   : MPEG-4 Visual
Format profile                           : Simple@L1
Format settings, BVOP                    : No
Format settings, QPel                    : No
Format settings, GMC                     : No warppoints
Format settings, Matrix                  : Default (H.263)
Codec ID                                 : 20
Duration                                 : 2mn 15s
Bit rate mode                            : Constant
Bit rate                                 : 281 Kbps
Width                                    : 720 pixels
Height                                   : 405 pixels
Display aspect ratio                     : 16:9
Frame rate mode                          : Constant
Frame rate                               : 29.970 (30000/1001) fps
Color space                              : YUV
Chroma subsampling                       : 4:2:0
Bit depth                                : 8 bits
Scan type                                : Progressive
Compression mode                         : Lossy
Bits/(Pixel*Frame)                       : 0.032
Stream size                              : 4.52 MiB (67%)
Writing library                          : Lavc58.54.100
Encoded date                             : UTC 1904-01-01 00:00:00
Tagged date                              : UTC 1904-01-01 00:00:00

Audio
ID                                       : 2
Format                                   : AAC
Format/Info                              : Advanced Audio Codec
Format profile                           : LC
Codec ID                                 : 40
Duration                                 : 2mn 15s
Duration_LastFrame                       : -19ms
Bit rate mode                            : Constant
Bit rate                                 : 129 Kbps
Channel(s)                               : 2 channels
Channel positions                        : Front: L R
Sampling rate                            : 48.0 KHz
Frame rate                               : 46.875 fps (1024 spf)
Compression mode                         : Lossy
Stream size                              : 2.07 MiB (31%)
Default                                  : Yes
Alternate group                          : 1
Encoded date                             : UTC 1904-01-01 00:00:00
Tagged date                              : UTC 1904-01-01 00:00:00


  



  Can you tell me what's wrong with the video file ??

  



  Best regards !

  


• ffmpeg record screen file formats

  3 avril 2020, par New_Dev

  Good day,
I'm currently writing a bash script which records the screen under certain conditions. The problem is that only avi works as a file extension for recording the screen. This script is going to be used on an Raspberry Pi and currently I get on a decent virtual machine only 10-20 fps (goal would be around 30 fps). I think .avi is not suited for my project. But .mpeg and .mp4 are not working for recording. I tried recording with .avi and then converting it in .mp4, but I have limited memory and .avi ist just too big in size. I use currently the following command :

  



  ffmpeg -f x11grab -y -r 30 -s 960x750 -i :0.0+0,100 -vcodec huffyuv ./Videos/out_$now.avi
//$now is the current date and time


  



  So I wanted to know if I need some special packages from ffmpeg to record with for example .mp4 or if there are other file formats available for ffmpeg screen recording.

  



  Edit :
I found that the codec libx264 for mp4 works, but the fps drop until they hit5 fps, which is definetly too low. The recorded video appeared like being a fast forward version of the recorded screen.

  



  With mpeg4 for mpeg I reached over 30 fps, but the video qualitywas very bad.

  



  It appears that even my big avi-files look like being played fast forward. Is there something I do wrong ?

  



  Is there a good middle way, where I get a decend video quality, good fps (20+) and a file which isn't too big ?

  



  Edit 2 :
I tried recording it with .avi and converting it afterwards. Just converting with ffmpeg -i test.avi -c:a aac -b:a 128k -c:v libx264 -crf 23 output.mp4 
resulted in the same framedrops as if I was recording with .mp4. But when I cut a littlebit of the beginning of the video and named the outputfile .mp4, the size became much smaller. But when I started the cutting at 0:00:00 (so tried just converting), it just changed the file format without converting it (so the size stayed the same). Any ideas ?