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• avformat/matroskaenc : Add option to shift data to write cues at front

  9 janvier 2022, par Andreas Rheinhardt

  avformat/matroskaenc : Add option to shift data to write cues at front
  This is similar to the faststart option of the mov muxer, yet
  
  in contrast to it it works together with reserve_index_space
  
  (the equivalent to reserved_moov_size) : If the reserved space
  
  does not suffice, the data is shifted ; if not, the Cues are
  
  written at the front without shifting the data.
  
  Several tests that cover (not only) this have been added.
  Implements #7017.
  Signed-off-by : Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
  

  • [DH] doc/muxers.texi
  • [DH] libavformat/matroskaenc.c
  • [DH] libavformat/version.h
  • [DH] tests/fate/matroska.mak
  • [DH] tests/ref/fate/matroska-dovi-write-config7
  • [DH] tests/ref/fate/matroska-move-cues-to-front
  • [DH] tests/ref/fate/matroska-ms-mode

• FFMPEG, the penultimate image from the .txt file doesn't show in the video

  25 octobre 2019, par ArmKh

  I’m trying to create a video from the images using ffmeg. Actually, the creating of the video works but there is a small problem. I have a text file with the names of the images (paths) which I’m using in the video. The file looks like this

  file 'image1.jpg'
  
  file 'image2.jpg'
  
  file 'image3.jpg'
  
  file 'image4.jpg'
  
  file 'image5.jpg'

  And the ffmeg command is following

  ffmpeg -y -r 1/5 -f concat -safe 0 -i imagenames.txt -i some_audio.mp3 -c:v libx264 -vf fps=30 -pix_fmt yuv420p -t 30 output.mp4

  This video should keep the frame on every image for 5 seconds. But the problem is the penultimate image ( image4 in this case ) is not being shown in the video. So, it keeps on image3 10 seconds and moves to image5

  So, the video in seconds looks like this

  [image1] -> [image2] -> [image3] -> [image4] -> [image5]
  5sec        5sec       10sec        0sec        5sec

  And the problem is not with the image4 exactly. In case of swapping image3 and image4, the video will skip image3

  [image1] -> [image2] -> [image4] -> [image3] -> [image5]
  5sec        5sec       10sec        0sec        5sec

  Hope you’ll have any suggestions to fix this issue

• ffprobe does not show packet size of a mpeg transport stream as 188 bytes

  16 octobre 2015, par CompNet

  I created a transport stream from a H.264 encoded file using the following ffmpeg command :

  ffmpeg -i encoded.mp4 -c copy -map 0 -vbsf h264_mp4toannexb mpegts sample.ts

  Now I want to check the frames and packets within the transport stream. I used

  ffprobe -show_frames

  which shows the frame details for audio and video frames. But I’m confused about the pkt_size field. Is it the actual frame size of each elementary stream of audio and video (I/B/P frames) ?

  Also, when I run

  ffprobe -show_packets

  is it supposed to give each packet details in the transport stream ? Because the size field of each packet is not 188 bytes, rather it is same as the pkt_size I got with -show_frames.

  Could someone please explain why the size in -show_packets of transport stream is not 188 bytes ? Did I do anything wrong while multiplexing mp4 to TS ?