Recherche avancée

Sur d’autres sites (6474)

• FFmpeg : With 1 720p and 1 1080p video, how can I upscale the 1st one to 1080p and hstack them in one command ?

  4 juillet 2021, par YousufSSyed

  This is the command I have right now, but it only works for videos with the same height :

  


  ffmpeg -i "video 1.mp4" -i "video 2.mp4" -c:a copy c:v h264_amf -filter_complex "hstack,format=yuv420p" "Output video.mp4" 


  


  

  • video 1.mp4 is the 720p one

  


  • video 2.mp4 is the 1080p one

  


  


  I need to keep the audio for the 1st video but not the 2nd one, the 2nd one doesn't have audio. I tried adding [0:v]scale=-1:1080; before hstack but that doesn't work.

  


• ac3enc : allow Dolby Pro Logic IIz as the Dolby Surround EX mode.

  18 février 2014, par Tim Walker

  ac3enc : allow Dolby Pro Logic IIz as the Dolby Surround EX mode.
  This is actually defined in the A/52 specification.
  

  • [DH] libavcodec/ac3enc.h
  • [DH] libavcodec/ac3enc_opts_template.c

• FFMPEG Re-muxing .MKV to MP4\MV4 while retaining Dolby Digital Plus [closed]

  30 décembre 2020, par David F

  I would be grateful if anyone could help me out here. I'm remuxing a large number of video files from .MKV to .MP4\M4V so they play on the Apple platform (including the TV App) without any issues. It has been a bit of a learning curve, but I’m so close now. It's important NOT to convert, but to remux.

  


  I have achieved the ability to remux 4K HDR with Dolby Digital Plus in a .MKV to 4K HDR with Dolby Digtial 5.1. MP4. The issue is retaining the Dolby Digital Plus. This contains the ATMOS information for object based sound.

  


  The media players on Apple reports Dolby Digital Plus for the .MKV and Dolby Digital 5.1 for .MP4

  


  I'm using FFMPEG with the following command :-

  


  ffmpeg -i original.mkv -c:v copy -c:a eac3 -tag:v hvc1 output.mp4

  


  Output from MediaInfo (note .MKV contains only 1 video and 1 audio track)

  


  Audio -----Original.mkv

  


  

  • ID : 2

  


  • Format : E-AC-3 JOC

  


  • Format/Info : Enhanced AC-3 with Joint
Object Coding

  


  • Commercial name : Dolby Digital Plus with Dolby
Atmos

  


  • Codec ID : **A_**EAC3

  


  • Duration : 51 min 51 s

  


  • Bit rate mode : Constant

  


  


  Audio ----- Remuxed .mp4

  


  

  • ID : 2

  


  • Format : E-AC-3

  


  • Format/Info : Enhanced AC-3

  


  • Commercial name : Dolby Digital Plus

  


  • Codec ID : ec-3

  


  • Duration : 51 min 51 s

  


  • Bit rate mode : Constant

  


  


  The remux operation finished in about 1 minute for a 8Gb 4k video file, so we I know there is no reencoding. My theory is the stream is still a E-AC-3 with Joint Object Control, but its marked as a E-AC-3.

  


  I can see that .mp4 can take E-AC-3 Joint Object Control (JOC) with the demo files from Dolby labs.

  


  I've also remuxed an MKV to MKV and able to see the same result. The JOC markings have been removed with FFMPEG

  


  My ask is, does anyone have any knowledge of how to remux and keep Enhanced AC-3 with Joint Object Control with FFMPEG. Does FFMPEG support this ?

  


  Or know if just editing the Format, Format/Info, and Code ID is enough and the sound information in my .MP4\M4V is E-AC-3 JOC. If so can I just edit the media info, if so how ?

  


  I know Dolby Labs to allow free remuxing of Dolby Digital Plus/ Atmos with sample code and information they have uploaded onto Github for developers. I just wonder if FFMPEG supports it

  


  Thanks in advanced.

  


  David