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• how can i stop ffmpeg when no new frame come from /dev/video0

  16 mai 2022, par itirou tarou

  I am now modifying stream from camera with our program(programA) and output as .ts files like below.

  


  camera => programA => /dev/video0 => ffmpeg => .ts files

  


  When camera stopped, programA stop automatically and no new frame arrive to /dev/video0.
I want ffmpeg stop automatically in such situation.
What ffmpeg option should I use ?
Currently I'm using option below, but ffmpeg doesn't stop.

  


  ffmpeg -f video4linux2 -i /dev/video0 -vsync vfr -f hls -c:v h264_nvenc out.m3u8

  


• How to re-encode a 120fps (or higher) MP4 from my Samsung Galaxy to a 30fps (example) so it plays on Windows like it does on the Samsung

  21 septembre 2022, par remark70

  I have some high fps slow-motion videos (mp4) that I've recorded on my phone, but when I copy them to windows and play them back, they play at the normal speed (or they play really fast), unless I slow down playback but this isn't a good result.

  


  What I'd like to do is re-encode (if that's the right word) the video to a standard fps (such as 30) to get a longer video (keeping all the frames), i.e. a 10 second 120fps would end up being a 40 second video at 30fps.

  


• Start and end time of MoviePy's VideoClip not working

  21 mars 2024, par ernesto casco velazquez

  I'm trying to add captions to a video. The desired outcome is to show each word in the exact moment is being said.

  


  I have a method that gives me the accurate time start and end per each word :

  


  def get_words_per_time(audio_speech_file):
    model = whisper.load_model("base")
    transcribe = model.transcribe(
        audio=audio_speech_file, fp16=False, word_timestamps=True
    )
    segments = transcribe["segments"]
    words = []

    for seg in segments:
        for word in seg["words"]:
            words.append(
                {
                    "word": word["word"],
                    "start": word["start"],
                    "end": word["end"],
                    "prob": round(word["probability"], 4),
                }
            )
    return words


  


  Then I have a code that uses MoviePy to create TextClip and assing a given start and end time per pair of words (I know there are redundant statements, srry) :

  


  def generate_captions(
    words,
    font="Komika",
    fontsize=32,
    color="White",
    align="center",
    stroke_width=3,
    stroke_color="black",
):
    text_comp = []
    for i in track(range(0, len(words), 2), description="Creating captions..."):
        word1 = words[i]
        if i + 1 < len(words):
            word2 = words[i + 1]
        text_clip = TextClip(
            f"{word1['word']} {word2['word'] if i + 1 < len(words) else ''}",
            font=font,  # Change Font if not found
            fontsize=fontsize,
            color=color,
            align=align,
            method="caption",
            size=(660, None),
            stroke_width=stroke_width,
            stroke_color=stroke_color,
        )
        text_clip = text_clip.set_start(word1["start"])
        text_clip = text_clip.set_end(
            word2["end"] if i + 1 < len(words) else word1["end"]
        )
        text_comp.append(text_clip)
    return text_comp


  


  Finally, I concatenate the words into a single video :

  


  vid_clip = CompositeVideoClip(
    [vid_clip, concatenate_videoclips(text_comp).set_position(("center", 860))]
)


  


  The output is this, but you can clearly see the words are not flowing with the speech. They somehow move faster as if the start/end time did not matter. Here's the video

  


  The words with their respective start/end time, look like this :

  


  [
    {
        'word': 'This',
        'start': 0.0,
        'end': 0.22,
        'prob': 0.805
    },
    {
        'word': 'is',
        'start': 0.22,
        'end': 0.42,
        'prob': 0.9991
    },
    {
        'word': 'a',
        'start': 0.42,
        'end': 0.6,
        'prob': 0.999
    },
    {
        'word': 'test,
        ',
        'start': 0.6,
        'end': 1.04,
        'prob': 0.9939
    },
    {
        'word': 'to',
        'start': 1.18,
        'end': 1.3,
        'prob': 0.9847
    },
    {
        'word': 'show',
        'start': 1.3,
        'end': 1.54,
        'prob': 0.9971
    },
    {
        'word': 'words',
        'start': 1.54,
        'end': 1.9,
        'prob': 0.995
    },
    {
        'word': 'does',
        'start': 1.9,
        'end': 2.16,
        'prob': 0.997
    },
    {
        'word': 'not',
        'start': 2.16,
        'end': 2.4,
        'prob': 0.9978
    },
    {
        'word': 'appear.',
        'start': 2.4,
        'end': 2.82,
        'prob': 0.9984
    },
    {
        'word': 'At',
        'start': 3.46,
        'end': 3.6,
        'prob': 0.9793
    },
    {
        'word': 'their',
        'start': 3.6,
        'end': 3.8,
        'prob': 0.9984
    },
    {
        'word': 'proper',
        'start': 3.8,
        'end': 4.22,
        'prob': 0.9976
    },
    {
        'word': 'time.',
        'start': 4.22,
        'end': 4.72,
        'prob': 0.999
    },
    {
        'word': 'Thanks',
        'start': 5.04,
        'end': 5.4,
        'prob': 0.9662
    },
    {
        'word': 'for,
        ',
        'start': 5.4,
        'end': 5.66,
        'prob': 0.9941
    },
    {
        'word': 'watching.',
        'start': 5.94,
        'end': 6.36,
        'prob': 0.7701
    }
]


  


  What could be causing this ?