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• ffmpeg can not open video file while PotPlayer and VLCPlayer can

  13 décembre 2020, par popova-ksiusha912

  Win10

  


  Video file(21.83MB) :https://www.mediafire.com/file/7b7w8ssio32qo2p/sample.flv/file

  


  Pot Player and VLC Player can open this file without any problem.

  


  But ffmpeg,ffplay,ffprobe can not open it.

  


  Is there any way to make ffmpeg recognize this video file ?

  


  C:\external>ffmpeg -v 9 -loglevel 99 -i sample.flv
ffmpeg version n4.3.1-26-gca55240b8c Copyright (c) 2000-2020 the FFmpeg developers
built with gcc 9.3-win32 (GCC) 20200320
configuration: --prefix=/ffbuild/prefix --pkg-config-flags=--static --pkg-config=pkg-config --cross-prefix=x86_64-w64-mingw32- --arch=x86_64 --target-os=mingw32 --enable-version3 --disable-debug --disable-w32threads --enable-pthreads --enable-iconv --enable-zlib --enable-libxml2 --enable-libfreetype --enable-libfribidi --enable-gmp --enable-lzma --enable-fontconfig --enable-opencl --enable-libvmaf --disable-vulkan --enable-libvorbis --enable-amf --enable-libaom --disable-avisynth --enable-libdav1d --disable-libdavs2 --enable-ffnvcodec --enable-cuda-llvm --disable-libglslang --enable-libass --enable-libbluray --enable-libmp3lame --enable-libopus --enable-libtheora --enable-libvpx --enable-libwebp --enable-libmfx --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-librav1e --disable-librubberband --enable-schannel --enable-sdl2 --enable-libsoxr --enable-libsrt --enable-libtwolame --disable-libvidstab --disable-libx264 --disable-libx265 --disable-libxavs2 --disable-libxvid --enable-libzimg --extra-cflags=-DLIBTWOLAME_STATIC --extra-cxxflags= --extra-ldflags=-pthread --extra-libs=-lgomp
libavutil 56. 51.100 / 56. 51.100
libavcodec 58. 91.100 / 58. 91.100
libavformat 58. 45.100 / 58. 45.100
libavdevice 58. 10.100 / 58. 10.100
libavfilter 7. 85.100 / 7. 85.100
libswscale 5. 7.100 / 5. 7.100
libswresample 3. 7.100 / 3. 7.100
Splitting the commandline.
Reading option '-v' ... matched as option 'v' (set logging level) with argument '9'.
Reading option '-loglevel' ... matched as option 'loglevel' (set logging level) with argument '99'.
Reading option '-i' ... matched as input url with argument 'sample.flv'.
Finished splitting the commandline.
Parsing a group of options: global .
Applying option v (set logging level) with argument 9.
Successfully parsed a group of options.
Parsing a group of options: input url sample.flv.
Successfully parsed a group of options.
Opening an input file: sample.flv.
[NULL @ 000001e044da4580] Opening 'sample.flv' for reading
[file @ 000001e044da4e80] Setting default whitelist 'file,crypto,data'
Probing flv score:100 size:2048
Probing mp3 score:1 size:2048
[flv @ 000001e044da4580] Format flv probed with size=2048 and score=100
[flv @ 000001e044da4580] Before avformat_find_stream_info() pos: 13 bytes read:32768 seeks:0 nb_streams:0
[flv @ 000001e044da4580] type:18, size:626, last:-1, dts:0 pos:21
[flv @ 000001e044da4580] type:8, size:4, last:-1, dts:0 pos:662
[flv @ 000001e044da4580] 1 AF 0
[flv @ 000001e044da4580] type:8, size:287, last:-1, dts:0 pos:681
[flv @ 000001e044da4580] 1 AF 0
[flv @ 000001e044da4580] type:9, size:13245, last:-1, dts:0 pos:983
[flv @ 000001e044da4580] 0 27 0
[NULL @ 000001e044e4bd80] missing picture in access unit with size 13240
[extract_extradata @ 000001e044e50600] No start code is found.
[flv @ 000001e044da4580] After avformat_find_stream_info() pos: 14235 bytes read:65845 seeks:3 frames:1
sample.flv: could not find codec parameters
Input #0, flv, from 'sample.flv':
Metadata:
d_cate : 1
d_client : 10001
dy_app_version : 6.3.6.1
dy_device_model : HONOR YAL-AL50 YAL-AL50
dy_level : Level51
dy_live_start_time: Sat Nov 28 22:05:50 GMT+08:00 2020
dy_location : null
dy_network : 4G 4
dy_os_version : 29
dy_profile : High
dy_pusher_version: 1.3.3
dy_timezone : Asia/Shanghai?
hasWatermark : 1
encoder : Lavf56.40.101
cdn_ip : 61.156.196.105
Duration: 00:01:14.46, start: 0.000000, bitrate: N/A
Stream #0:0, 1, 1/1000: Audio: aac, 44100 Hz, stereo, 98 kb/s
Stream #0:1, 0, 1/1000: Video: h264, 1 reference frame, none, 2048 kb/s, 1k tbn
Successfully opened the file.
At least one output file must be specified
[AVIOContext @ 000001e044dadd40] Statistics: 65845 bytes read, 3 seeks
C:\external>


  


• Rolling screen capture with ffmpeg on windows

  11 décembre 2020, par gap210

  I have the following code to capture a video stream from my webcam. I use ffmpeg to write to named windows pipe, then read it with python and display with opencv. The thing is that the opencv stream is 'rolling' as shown here https://www.youtube.com/watch?v=H78TRo3DZIo

  


  If I capture the output to a video instead of a pipe, with the command :

  


  ffmpeg -f dshow -video_size 1920x1080 -framerate 60 -i video="USB Video" -c:v copy out.avi

  


  everything looks fine. What should I change to achieve the desired effect ? (non-rolling stream)

  


  My code below :

  


  import cv2
import time
import subprocess
import numpy as np

w, h = 800, 600

# Get frame generator
gen = ffmpegGrab()

# Get start time
start = time.time()

# Read video frames from ffmpeg in loop
nFrames = 0
cmd = 'C:/Users/......./Downloads/ffmpeg-4.3.1-2020-11-19-full_build/bin/ffmpeg.exe -f dshow -framerate 60 -video_size 800x600 -i video="USB Video" -pix_fmt bgr24 -vcodec rawvideo -f image2pipe -'

proc = subprocess.Popen(cmd, stdout=subprocess.PIPE, stderr=subprocess.STDOUT, shell=True, bufsize=10**9)
while True:
    # Read next frame from ffmpeg

    frame = proc.stdout.read(w * h * 3)
    frame = np.frombuffer(frame, dtype=np.uint8).reshape((h, w, 3))
    cv2.imshow('screenshot', frame)

    if cv2.waitKey(1) == ord("q"):
        break

    fps = nFrames / (time.time() - start)
    print(f'FPS: {fps}')

cv2.destroyAllWindows()


  


• Problems with ffmpeg input filenames when using bash script

  25 septembre 2020, par Nick Styles

  I'm trying to use ffmpeg to convert some .m4a audio files to .mp3, and have come across something that has me stumped. I'd like to create the .mp3 in the same location and with the same filename as the .m4a, and so I'm using a combination of find/exec and a bash script to do this, as follows :

  


  find /Volumes/Untitled/ -name '[!.]*' -name '*.m4a' -exec ./m4atomp3.sh {} \;


  


  where m4atomp3.sh looks like :

  


  #!/usr/bin/env bash
[[ -f "$1" ]] || { echo "$1 not found" ; exit 1 ; }
P="$1"
echo "$P is the full filename"
filename=${P%.*}
echo "$filename is the stripped filename"
m4afilename=\"$filename.m4a\"
echo "$m4afilename is the input filename"
mp3filename=\"$filename.mp3\"
echo "$mp3filename is the output filename"
mycmd="/Users/nickstyles/Downloads/ffmpeg -i "$m4afilename" -codec:a libmp3lame -qscale:a 2  -nostdin "$mp3filename
echo $mycmd
$mycmd


  


  Whenever I try this, it fails because ffmpeg doesn't find the file, seemingly because of the whitespace in the filename, e.g if the file was called /Volumes/Untitled/My M4As/My M4A.m4a I would see :

  


  ffmpeg version N-99346-g003b5c800f-tessus  https://evermeet.cx/ffmpeg/  Copyright (c) 2000-2020 the FFmpeg developers
  built with Apple clang version 11.0.0 (clang-1100.0.33.17)

[configuration details]

"/Volumes/Untitled/My: No such file or directory


  


  However, if I just paste what is returned by echo $mycmd into the command line, e.g :

  


  /Users/nickstyles/Downloads/ffmpeg -i "/Volumes/Untitled/My M4As/My M4A.m4a" -codec:a libmp3lame -qscale:a 2 -nostdin "/Volumes/Untitled/My M4As/My M4A.mp3"


  


  then it works absolutely fine. I'm sure I'm missing something very obvious, which hopefully someone can spot !