Recherche avancée

Sur d’autres sites (9895)

• FFmpeg get frame rate

  22 septembre 2021, par zhin dins

  I have several images and I am reproducing them in 78.7ms, I am creating like the 80s video effect. But, I am unable to find the correct ms, and this images with the original videos are unsync.

  


  I dumped the video to images using this command => ffmpeg -i *.mp4 the80effect/img-%d.jpg And now, I have 48622 frames. The video FPS is 24

  


  So, 48622/24 = 2025 +- I cannot use 2025ms since those images will load very slow. And the and the approximate value is 78.7ms per frame/image

  


  How can I find the correct value ? The video duration in seconds is 2026. I have tried all math to find this but I'm failing. How many images (one frame) per msCould you help me ? Thank you.

  


• ffmpeg keyframe control on single image + audio

  21 juin 2022, par user3190036

  I have scoured every related StackOverflow question I can find and none of them solved the issue, apologies in advance if I missed the one that would have worked.

  


  The application I am working on converts a video or audio file to an mp4, and later on the server to an hls playlist. I just implemented audio and I wanted a background image. After reading through various options on StackOverflow I settled on the following args :

  


  -y -i "C:\path\ExternalAudioBackground.png" -i "C:\path\Audio.mp3" -vf scale=1280:720:force_original_aspect_ratio=decrease,pad=1280:720:-1:-1:color=black -c:a copy -vcodec libx264 -pix_fmt yuv420p "C:\path\external_media_file.mp4"


  


  This set of args was chosen because it is instantaneous due to -c:a copy as well as constraints to ensure all videos have the same aspect ratio and encoding.

  


  The issue is when converting this to an hls stream the stream fails to play (in video.js player, and also vlc) with the message :

  


  VIDEOJS : WARN : Segment with index 0 from playlist 0-https://domain/video.m3u8 has a duration of 464.96 when the reported duration is 0.04 and the target duration is 0.04. For HLS content, a duration over the target duration may result in playback issues. See the HLS specification section on EXT-X-TARGETDURATION for more details : https://datatracker.ietf.org/doc/html/draft-pantos-http-live-streaming-23#section-4.3.3.1 https://datatracker.ietf.org/doc/html/draft-pantos-http-live-streaming-23#section-4.3.3.1

  


  Adding -loop 1 to the start increases the processing time from milliseconds to minutes, but produces a working file

  


  Adding -r 1 and -loop 1 takes longer to process than without -r (!?)

  


  Adding -stream_loop 116 (116 is the length of the audio in seconds divided by 4, the desired hls segment size) before the image input loops the first 4 seconds of the audio over and over

  


  adding -g 96 (96 is the fps * 4)

  


  In case relevant, the hls encoding arguments look like this :

  


  -safe 0 -f concat -i listOfFiles.txt -c:a aac -ar 48000 -b:a 128k -vcodec copy -crf 20 -g 48 -keyint_min 48 -sc_threshold 0 -b:v 2500k -maxrate 2675k -bufsize 3750k -hls_time 4 -hls_playlist_type vod  -hls_segment_filename segment-%03d.ts result.m3u8


  


  listOfFiles.txt always contains only one file in the case being discussed.

  


  How can I achieve this with the minimum processing time but still have the file convertable to HLS ?

  


• Is there any open source HLS segmenter that supports Apple Low Latency HLS ? [closed]

  13 juillet 2021, par Marcus Wichelmann

  Currently I'm using FFmpeg to produce a HLS segmented stream to deliver some live content to our users. Now I'd like to reduce latency by using Apples latest Low Latency Standard which is unfortunately quite complex and the only standard that is supported on Apple devices.

  


  But I have not yet found any open source implementation of this. Do you know of any project that works on implementing the whole Apple LL-HLS standard including the latest #EXT-X-PRELOAD-HINT additions ?

  


  What do you use as segmenter for your low latency ABR streams ?