Recherche avancée

Sur d’autres sites (6313)

• FFMPEG store method : Separated fields ?

  17 février 2021, par Caloux Fld

  I am using FFMPEG with GPU h264_nvenc codec to upscale MPEG2 interlaced files.
h264_nvenc generate h264 with the store method : Separate fields (in mediaInfo) instead of the store method : Interleaved fields. These files with separate fields seems to be incompatible with tools like GVG Edius. How to change this store method ?

  


  with ffmpeg version N-92103-gebc3d04b8d Copyright (c) 2000-2018 the FFmpeg developers
built with gcc 8.2.1 (GCC) 20180813

  


  Command FFMPEG :

  


   -ss 00:14:45  -hwaccel cuda   -c:v mpeg2_cuvid  -i "input.mpg" -t 00:00:10 -vf "scale=if(gt(dar\,1.6)\,1920\,1460):1080:flags=lanczos:interl=1" -c:v h264_nvenc  -pix_fmt nv12 -flags +ilme+ildct -b:v 16M -maxrate:v 22M -bufsize:v 8M -profile:v high -level:v 4.1 -rc:v vbr  -coder:v cabac -f mp4 -y "inputUpscaled_GPU.MP4"


  


  mediainfo testUpscale_GPU.MP4 :

  


  Format                                   : AVC
Format/Info                              : Advanced Video Codec
Format profile                           : High@L4.1
Format settings                          : CABAC / 1 Ref Frames
Format settings, CABAC                   : Yes
Format settings, Reference frames        : 1 frame
Codec ID                                 : avc1
Codec ID/Info                            : Advanced Video Coding
Duration                                 : 10 s 0 ms
Bit rate mode                            : Variable
Bit rate                                 : 17.8 Mb/s
Maximum bit rate                         : 22.0 Mb/s
Width                                    : 1 460 pixels
Height                                   : 1 080 pixels
Display aspect ratio                     : 4:3
Frame rate mode                          : Constant
Frame rate                               : 25.000 FPS
Original frame rate                      : 50.000 FPS
Color space                              : YUV
Chroma subsampling                       : 4:2:0
Bit depth                                : 8 bits
Scan type                                : Interlaced
Scan type, store method                  : Separated fields
Scan order                               : Top Field First
Bits/(Pixel*Frame)                       : 0.451
Stream size                              : 21.2 MiB (99%)
Codec configuration box                  : avcC


  


• script doesnt recognize bars / lenght right for cutting audio , ffmpeg terminal

  14 avril 2024, par totzillarbeats

  This Terminal script doesnt recognize bars / lenght right for cutting audio , maybe somebody knows whats wrong with the calculation :)

  


  Would be happy about any help the cutting already works !

  


  #!/bin/bash

# Function to extract BPM from filename

get_bpm() {
    local filename="$1"
    local bpm=$(echo "$filename" | grep -oE '[0-9]{1,3}' | head -n1)
    echo "$bpm"
}

# Function to cut audio based on BPM
cut_audio() {
    local input_file="$1"
    local bpm="$2"
    local output_file="${input_file%.*}_cut.${input_file##*.}" # Appends "_cut" to original filename

    # Define the number of beats per bar (assuming 4 beats per bar)
    beats_per_bar=4

    # Calculate the duration of each bar in seconds
    bar_duration=$((60 * beats_per_bar / bpm))

    # Define start and end times for each bar range
    start_times=(0 21 33 45 57 69 81 93 105 117 129 141)
    end_times=(20 29 41 53 65 77 89 101 113 125 137 149)

    # Iterate through each bar range
    for ((i = 0; i < ${#start_times[@]}; i++)); do
        start_time=${start_times[$i]}
        end_time=${end_times[$i]}
        echo "Cutting audio file $input_file at $bpm BPM for bar $((i + 1)) ($start_time-$end_time) for $bar_duration seconds..."

        # Cut audio for current bar range using ffmpeg
        ffmpeg -i "$input_file" -ss "$start_time" -to "$end_time" -c copy "$output_file"_"$((i + 1)).${input_file##*.}" -y
    done

    # Check if the output files are empty and delete them if so
    for output_file in "${output_file}"_*; do
        if [ ! -s "$output_file" ]; then
            echo "Output file $output_file is empty. Deleting..."
            rm "$output_file"
        fi
    done

    echo "Audio cut and saved as $output_file"
}


# Main script
if [ "$#" -eq 0 ]; then
    echo "Usage: $0 [audio_file1] [audio_file2] ..."
    exit 1
fi

for file in "$@"; do
    bpm=$(get_bpm "$file")
    if [ -z "$bpm" ]; then
        echo "Error: No BPM found in filename $file"
    else
        cut_audio "$file" "$bpm"
    fi
done


  


  Maybe its only the math calc in the beginning but idk :)

  


  If you need more details just lmk

  


• two pass encoding in ffmpeg

  7 août 2015, par Robin

  I will be encoding different videos uploaded by the user asynchronously in my server. I saw this post, and according to this, this is how to endcode two pass encoding :

  ffmpeg -y -i input -c:v libx264 -preset medium -b:v 555k -pass 1 -c:a libfdk_aac -b:a 128k -f mp4 /dev/null && \
  
  
  
  ffmpeg -i input -c:v libx264 -preset medium -b:v 555k -pass 2 -c:a libfdk_aac -b:a 128k output.mp4

  I noticed the -pass 1 and -pass 2 flags. But I tried encoding a video by just giving it a -pass 2 flag without first encoding in -pass 1 flag. Although I had this warning, it executed anyway :

  2nd pass has more frames than 1st pass

  So, my concern is how will ffmpeg know which one is the first pass so that it can do its pass 2 encoding ? And since many videos will be uploaded simultaneously I can’t keep them all at the /dev/null won’t it will replace one with another. So how can I manage it ?

  Your help and guidance will be very much appreciated.

  Thank you.

  Upadate

  ffmpeg cmd :

  ffmpeg -i input.mp4 -codec:v libx264 -tune zerolatency -profile:v main -preset medium -b:v 1500k -maxrate 1500k -bufsize 15000k -s hd720 -threads 0 -pass 1 -an -f mp4 /dev/null
  
  
  
  ffmpeg -i input.mp4 -codec:v libx264 -tune zerolatency -profile:v main -preset medium -b:v 1000k -maxrate 1000k -bufsize 10000k -s hd720 -threads 0 -pass 2 -codec:a libfdk_aac -movflags +faststart output.mp4