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• fftools/ffmpeg : stop using av_stream_get_end_pts()

  1er avril 2022, par Anton Khirnov

  fftools/ffmpeg : stop using av_stream_get_end_pts()
  It retrieves the muxer's internal timestamp with under-defined
  
  semantics. Continuing to use this value would also require
  
  synchronization once the muxer is moved to a separate thread.
  Replace the value with last_mux_dts.
  

  • [DH] fftools/ffmpeg.c

• Web Based Playback of iOS Videos with Orientation Flag

  3 mars 2012, par shanee

  We just recently created an iPhone app for one of our system that allows users to upload picture and video content to our services. The last major hitch we are running into is how to handle videos that are uploaded in an orientation other than Horizontal Right. Apparently if your playback system does not account for the orientation flag sent with the video then it will play upside down or sideways.

  The correct approach appears to be that the playback system should take the orientation flag into account just prior to playback. This is the way Apple handles it directly on the device as well as through Quicktime.

  SO my first hope is that someone is aware of a web based (HTML5 or Flash) player that is capable of rotating a video during playback based on either the video orientation metadata or based on a passed flag (we already have the necessary flag available in the DB if we need to just pass it manually). If you know of any such player then PLEASE SHARE !

  If you aren't aware of such a player, then has anyone had any luck rotating their videos using FFMPEG or MEncoder ? We did a few hours of testing last week and weren't able to get any decent results from the two heavy hitters mentioned there.

  Failing ALL OF THAT, is it possible to have the iPhone upload a video or image in a specified direction ?

  Any of the three will work for me, but I would prefer to do whatever is standard (if one exists).

  Any help is much appreciated !

• ffmpeg - concatenate large set of video files - file names

  5 avril 2023, par bunnyisblack

  I'm trying to concatenate multiple video files. They all use the same codec and frame rate. Anyway concatenation isn't a problem. I've done it before.

  


  The problem is to automate it ?

  


  The answer here shows method 2 to be used in windows to concatenate files.
It's really easy :

  


  (echo file 'first file.mp4' & echo file 'second file.mp4' )>list.txt
ffmpeg -safe 0 -f concat -i list.txt -c copy output.mp4


  


  First, we make a list of video files (by manually tying them out). Second, we execute.

  


  The problem is that I have multiple video files located in a single directory. The video files are named similar to this :

  


  \450_01_videoName.mp4
\450_02_videoNameFoo.mp4
\450_04_videoNameMoo.mp4
\451_01_videoNameRoo.mp4
\451_02_videoNameHoo.mp4


  


  Now look at the above list and imagine that it's 200 lines big in a single folder. I'm trying to concatenate video 450 into 1, then video 451 into 1 file, etc.

  


  I'm trying to automate this process with a good thousand video files.

  


  I can do it semi manually. Use cmd to create a list of file and folder path. But then I would manually, file by file, have to copy and paste it to create that list.txt.

  


  Is there a way to automate this ? I've done this manually with 20 video files and it was painful (but better then using a stand alone software, as all the videos were done in a batch after all was set up).

  


  Cheers.

  


  I've done the process semi manually. It worked, but took more time that it needs to take.

  


  ------UPDATE

  


  This is how I tackled the problem. It was slow and painful.

  


  Firslty, I used cmd "dir /b > file.txt" to extract all the names of video files in that directory.

  


  Then I painfully wrote the BAT file manually (for videos up to 500) for each video I wanted to merge. I used a few notepad++ shortcuts, for example, replacing the number '45' with 'echo file 45', this ensured I didn't need to type 'echo file' manually for every line. Then I also copy-pasted manually for every line '>>list.txt'. I painfully had to write out the output file name 50 different times.

  


  h:
cd "h:\video directory"
echo file 450_01_video.mp4 > list.txt
echo file 450_02_videoMoo.mp4 >> list.txt
echo file 450_03_videoFoo.mp4 >> list.txt
echo file 450_04_videoLoo.mp4 >> list.txt
ffmpeg -safe 0 -f concat -i list.txt -c copy 450Video.mp4
echo file 451_01_video.mp4 > list.txt
echo file 451_02_videoMoo.mp4 >> list.txt
ffmpeg -safe 0 -f concat -i list.txt -c copy 451Video.mp4


  


  Now imagine a line for every single video file that I had to do manually.

  


  There has to be a simple for loop solution.

  


  ANSWER - SOLVED

  


  I've used Armali's solution.

  


  h:
cd "h:\video directory"

SETLOCAL ENABLEDELAYEDEXPANSION
set number=999
for %%f in (???_*.mp4) do (
    set name=%%f
    set before=!number!
    set number=!name:~0,3!
    if !number! gtr !before! call :concat
    echo file !name! >>list.txt
)

:concat
    ffmpeg -safe 0 -f concat -i list.txt -c copy %before%Video.mp4
    del list.txt


  


  The output video files were named 412Video.mp4. I used the dir /b file.txt command to extract the list of original files. I then copied them into excel, delimited them and used the tricks to extract the number, name, and remove duplicates etc. I then combined each record with output video as a ren command. E.g. ren 412video.mp4 412.name.location.mp4. I copied that into cmd for a fast rename.