Newest 'ffmpeg' Questions - Stack Overflow

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• how to get cmsamplebuffer data to avformate_open_input() function in FFMpeg ?

  17 mai 2018, par Shahrear Mahmud

  i want to stream apple mobile camera to a UDP port using FFMPEG. so far i have already done it from a video file. but now i want to do it live from apple mobile camera. some body can give me some clue for this. my head is spining for this solution? Please help me.

• Minimum duration in chunk size while converting to hls format using ffmpeg

  17 mai 2018, par Abhishek

  I am using ffmpeg to convert mp4 to .ts format. In the meta file generated I can see chunk size are random which is acceptable to me, but i need to specify minimum duration of chunk size. Like 15sec or 30sec. Currently I am using following command to convert the videos.

  ffmpeg -i ad1.mp4 -strict -2 -profile:v baseline -level 3.0 -start_number 0 -hls_list_size 0 -hls_segment_filename 'sample-%06d.ts' -f hls sample.m3u8

  Pastebin link for sample m3u8 file

• Android Trim mp4 file(remote,smb)

  17 mai 2018, par Djangorussia

  Task: trim mp4-video(remote) from n sec to m sec. For access use samba

  1) I try to find library using ffmpeg. Example. But this library doesn't support smb protocol.

  2)I try to use mp4parser. But I can't combine jcifs + mp4parser

  3)I tried to write the library myself. It's poor trick. Not like.

  How best to solve this problem. Need help(advice)

• A/V out of sync when using ffmpeg from mpeg-ts to dash

  17 mai 2018, par user3540646

  I'm using ffmpeg in order to convert MPEG-TS stream to MPEG-DASH. The mpeg-ts is h264 and aac_latm. Therefore I don't need to reencode the video. The command I use:

  ffmpeg -i http://10.0.0.211:55555/Ch%2011%20Kan -strict -2 -c:v copy -window_size 10 -extra_window_size 10 -use_template 1 -use_timeline 1 -f dash kan.mpd
  

  I'm copying the video codec by using -c:v copy and the audio codec is default to aac.

  That way I get DASH stream BUT the audio/video is out of sync!

  How can I fix it?

  Notes:

  1. If I reencode both audio and video like:

     ffmpeg -i http://10.0.0.211:55555/Ch%2011%20Kan -strict -2 -window_size 10 -extra_window_size 10 -use_template 1 -use_timeline 1 -f dash kan.mpd

  Then the audio/video is synced perfectly. But I do not want to reencode the video for nothing as I mentioned the video is already h264. (directly impact to performance)

  2. If I convert the MPEG-TS stream to mp4 file like:

     ffmpeg -i http://10.0.0.211:55555/Ch%2011%20Kan -strict -2 -c:v copy kan.mp4

  Then the audio/video is synced perfectly.

• Fastest seek speed and decoding with ffmpeg and x265 ProRes

  17 mai 2018, par Christopher Jarvis

  I'm trying to optimize seek speed with x265. No matter what encoding settings I try, ProRes still seeks more quickly/gracefully. This makes sense since it was built for editing, but I'm sure there's got to be something I'm missing to better improve x265.

  So far, -tune fastdecode, keyint=1, maxrate and -b (to remove B Frame calculations) yield the best results, but they're still unsatisfactory. I've been pouring over the docs but there's so much jargon I just don't understand. Perhaps another codec like VP9 / WebM would be better for this purpose?

  From what I can tell, there's no bottleneck with CPU, read speed or RAM... or GPU for that matter. Monitoring these processes show minimal drain. Is there just an amount of decoding in a highly compressed format like x265 that can't be circumvented?

  Thank you in advance for your help.