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• Why does menconder fps rate does not work ?

  27 février 2016, par ACR

  I’m using mencoder to create a video out of some .png files. The problem is that the frame rate doesn’t change, regardless of the -fps flag. The output video has different time lengths (in their properties), but the video’s size and speed are always the same (regardless of the FPS chosen).

  I just want to create a shorted video by using higher FPS rates. In short, a "time-lapse" of my original set of images. What am I doing wrong with mencoder ? I’m using the following command :

  mencoder mf://./IMG/images*.png -mf w=800:h=600:fps=20:type=png -ovc copy -oac copy -o video.avi

• Why menconder fps rate does not work ?

  2 mars 2016, par ACR

  I’m using mencoder to create a video out of some .png files. The problem is that the frame rate doesn’t change, regardless of the -fps flag. The output video has different time lengths (in their properties), but the video’s size and speed are always the same (regardless of the FPS chosen).

  I just want to create a shorted video by using higher FPS rates. In short, a "time-lapse" of my original set of images. What am I doing wrong with mencoder ? I’m using the following command :

  mencoder mf://./IMG/images*.png -mf w=800:h=600:fps=20:type=png -ovc copy -oac copy -o video.avi

• How to pass bytesArray as input and output in command array for FFmpeg execute ?

  11 avril 2023, par Rohit gupta

  I was working with FFmpeg library where I was developing microphone-based reading and writeing the audioData, where i got the challenge to process some audioData. but i dont want to store the files as outputstream or something as it will add additional delays.

  


  This was my code that i used

  


  implementation 'com.arthenica:mobile-ffmpeg-full:4.2.2.LTS'


  


  private fun processAudioAsChipmunk(audioData: ShortArray, record: AudioRecord): ShortArray {
        val sampleRate = record.sampleRate
        val channels = record.channelCount
        val filter = "asetrate=2*${sampleRate},aresample=48000,atempo=2"
        val outputData = audioData
        val cmd = arrayOf(
            "-y",
            "-i",
            fileName1,  // here input filepath is passed, i want it to be ByteArray(audioData)
            "-af",
            "asetrate=22100,atempo=1/2",
            fileName2 //here output filepath is passed, i want it to be ByteArray(outputData)
        )//Chipmunk

        FFmpeg.execute(cmd)
        return outputData
    }



  


  Now i wanted to read and write the audioData without storing and using it as filenames.

  


  the below code shows the code i'm using to read and write audio Data

  


  read = record!!.read(audioData, 0, minBuffer) //AudioRecord
val processedAudioData = processAudioAsChipmunk(audioData, record!!) // Here! 
write = player!!.write(processedAudioData, 0, read) //AudioTrack


  


  Post thought ->

  


  I tried below code but again failed to pass input and output stream instead of filename inside executeAsync

  


  https://github.com/arthenica/ffmpeg-kit


  


  fun executeFfmpegCommand(audioData: ShortArray, rubberbandPitch: Float = 1.0f): ShortArray {
        // Convert short array to byte array
        val byteBuffer = ByteBuffer.allocate(audioData.size * 2)
        byteBuffer.order(ByteOrder.nativeOrder())
        for (i in audioData.indices) {
            byteBuffer.putShort(audioData[i])
        }
        val inputData = byteBuffer.array()

        // Set input data as input stream
        val inputStream = ByteArrayInputStream(inputData)

        // Create output stream to store output data
        val outputStream = ByteArrayOutputStream()

        // Add rubberband filter to command to make audio sound like chipmunk
        val rubberbandFilter = "rubberband=pitch=${rubberbandPitch}"
        val commandWithFilter = arrayOf("-f", "s16le", "-ar", "44100", "-ac", "2", "-i", "-", "-af", rubberbandFilter, "-f", "s16le", "-")

        // Create ffmpeg session
        val session = FFmpegKit.executeAsync() // @!! HOW TO PASS CommandFilter, inputStream, outPutStream here !!@

        // Wait for session to complete
        session.wait()

        // Check if session was successful
        if (ReturnCode.isSuccess(session.returnCode)) {
            Log.e("FFmpeg", "FFmpeg execution failed with return code: ${session.returnCode}")
            return ShortArray(0)
        }

        // Convert output stream to short array
        val outputData = outputStream.toByteArray()
        val shortBuffer = ByteBuffer.wrap(outputData)
            .order(ByteOrder.nativeOrder())
            .asShortBuffer()
        val outputShortArray = ShortArray(shortBuffer.remaining())
        shortBuffer.get(outputShortArray)

        // Return output short array
        return outputShortArray
    }