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• ffmpeg copies and restreams HLS/TS stream to RTP/Janus but fails on HLS/fMP4 stream

  6 juin 2024, par puterboy

  I am using go2rtc to generate HLS streams to stream video from a PiCamera v3 running on an RPi5 for use in Octoprint.

  


  I also need to copy and restream the HLS stream to an RTP Janus server for Spaghetti detection.

  


  ffmpeg works fine on an HLS/TS (H264) stream but fails on a similar HLS/fMP4 (H264, H265, AAC) stream — however, for quality reasons, I would prefer to use an HLS/fMP4 stream.

  


  Specifically, I am running the following :

  


  ffmpeg -re -i  -an -c:v copy -an -f rtp rtp://127.0.0.1:17732?pkt_size=1300```


  


  It streams properly forever when STREAM_URL is in HLS/TS format but fails when in HLS/fMP4 format after about 3-4 frames.

  


  Running ffprobe gives the following :

  


  HLS/TS :

  


    Duration: N/A, start: 0.000000, bitrate: N/A
  Program 0
    Metadata:
      variant_bitrate : 192000
  Stream #0:0: Video: h264 (High) ([27][0][0][0] / 0x001B), yuv420p(tv, bt709), 1536x864, 15 tbr, 90k tbn
    Metadata:
      variant_bitrate : 192000


  


  HLS/fMP4 :

  


    Duration: N/A, start: 0.000000, bitrate: 1248005 kb/s
  Program 0
    Metadata:
      variant_bitrate : 192000
  Stream #0:0: Video: h264 (High) (avc1 / 0x31637661), yuv420p(tv, bt709), 1536x864, 1248005 kb/s, 90k tbr, 90k tbn (default)
    Metadata:
      variant_bitrate : 192000
      major_brand     : iso5
      minor_version   : 512
      compatible_brands: iso5iso6mp41


  


  

  • Why does ffmpeg succeed on a HLS/TS stream but fail on an HLS/fMP4 stream ?

  


  • Are there any parameters or simple envelope filters I can add to ffmpeg that will allow it to succeed on HLS/fMP4 streams, short of a computationally intensive re-transcoding ?

  


  


• Trouble trimming video by frame number with ffmpeg

  8 décembre 2023, par jgore200377

  I want to trim/split a video with ffmpeg using frames. The reason why is because I am using a Shot Transition Detection model which returns a probability of transition for every frame in the video.

  


  Using timestamps to cut the video has yielded bad results as the precision is not 100%.

  


  Ive tried this command which just outputs the entire video which is DEFINITELY not what I want

  


  ffmpeg -i video.mp4 -vf "trim=start_frame=100:end_frame=200,setpts=PTS-STARTPTS" -c:a copy output.mp4


  


  Ive also tried using python bindings with ffmpeg-python

  


  import ffmpeg

input_file = ffmpeg.input('video.mp4')
output_file = ffmpeg.output(input_file.trim(start_frame=1300, end_frame=1500), 'test_output.mp4')
ffmpeg.run(output_file)


  


  This doesnt work either and outputs a video with half of it being still with unpredictable length

  


  ---

  


  Ive visited some other sites but none seem to have this nailed down and it would be much appreciated if someone can answer how to use frames to trim/split a video with ffmpeg.

  


• Segmenting a video and adding text that differs in each segment [FFMPEG]

  31 octobre 2023, par Kal-Toh

  I have a folder full of videos I want to segment, resize and add text to. So far I've managed to segment and resize them.

  


  I'm trying to add text in a TikTok Style : [Kind of like][1] this but black text in a white background. (If that isn't possible, I'd be fine with just white text).

  


  I already have the font file(.oft file type, is that ok or does it need to be .ttf ?)
The video is being converted to 720x1280 (9:16) and I'd like the text to display at the top centre of the video, taking up roughly the top 25%.

  


  Further to this, and this is where I'm having trouble understanding the process :

  


  I'd like text at the bottom of the video in the same style, that would change each segment.

  


  For example :

  


  I have a 10 minute long video. I want to split this video into 60 second segments. Each segment will have a title (the same across each segment) and a sub title at the bottom that would differ for each segment (for example 'Part 1/10', 'Part 2/10' etc)

  


  I know I could run one command to segment each video, add the title and change the aspect ratio and a second command to add the bottom text, feeding in a variable based on the number of mp4 files in the folder, however that doesn't seem like the most efficient process. Is there a way to do this all in one command ?

  


  This is the command I'm using so far :

  


  ffmpeg_command = [
            'ffmpeg',
            '-i', os.path.join(input_folder, video_file),
            '-vf', f'scale=720:1280:force_original_aspect_ratio=decrease,pad=720:1280:(ow-iw)/2:(oh-ih)/2
            ,drawtext=text=\'{text}\':x=(w-tw)/2:y=(h/4)-th:fontsize=24:fontfile={font_path}:fontcolor=black:box=1:boxcolor=white',
            '-threads', '100',
            "-c:a", "copy",
            '-t', str(duration),
            '-segment_time', '160',  # 3 minutes
            '-reset_timestamps', '1',
            '-f', 'segment',
            os.path.join(output_subfolder, f'{video_name}_%03d.mp4')
        ]


  


  Although not styled the way I want it to be, it's a decent start and all else works fine.

  


  It's just the bottom text I can't figure.
[1] : https://i.insider.com/61aa608a983f360019c854a5?width=1300&format=jpeg&auto=webp