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• How to save frames to memory from video with ffmpeg gpu encoding ?

  6 juillet 2021, par Spetra

  I'm trying to extract frames from video and save them to memory(ram).
With CPU encoding, I don't have any problems :

  


  ffmpeg -i input -s 224x224 -pix_fmt bgr24 -vcodec rawvideo -an -sn -f image2pipe -


  


  But when I'm trying to use some NVIDIA GPU encoding, I'm always getting noisy images.
I tried to use different commands, but the result was always the same, on Windows and Ubuntu.

  


  ffmpeg -hwaccel cuda -i 12.mp4 -s 224x224 -f image2pipe - -vcodec rawvideo


  


  With saving JPG's on disk, I don't have any problems.

  


  ffmpeg -hwaccel cuvid -c:v h264_cuvid -resize 224x224 -i {input_video} \
     -vf thumbnail_cuda=2,hwdownload,format=nv12 {output_dir}/%d.jpg


  


  There was my python code for testing these commands :

  


  import cv2
import subprocess as sp
import numpy

IMG_W = 224
IMG_H = 224
input = '12.mp4'

ffmpeg_cmd = [ 'ffmpeg','-i', input,'-s', '224x224','-pix_fmt', 'bgr24',  '-vcodec', 'rawvideo', '-an','-sn', '-f', 'image2pipe', '-']


#ffmpeg_cmd = ['ffmpeg','-hwaccel' ,'cuda' ,'-i' ,'12.mp4','-s', '224x224','-f' , 'image2pipe' ,'-' , '-vcodec' ,'rawvideo']

pipe = sp.Popen(ffmpeg_cmd, stdout = sp.PIPE, bufsize=10)
images = []
encode_param = [int(cv2.IMWRITE_JPEG_QUALITY), 95]
cnt = 0
while True:
    cnt += 1
    raw_image = pipe.stdout.read(IMG_W*IMG_H*3)
    image =  numpy.fromstring(raw_image, dtype='uint8')     # convert read bytes to np
    if image.shape[0] == 0:
        del images
        break   
    else:
        image = image.reshape((IMG_H,IMG_W,3))
        

    cv2.imshow('test',image)
    if cv2.waitKey(1) & 0xFF == ord('q'):
        break

pipe.stdout.flush()
cv2.destroyAllWindows()


  


• Save first an last frame as a picture

  7 octobre 2020, par Oscar Thees

  I try to cut out the last and the first frame of videos. The following commands work for specific files :

  


  ffmpeg -i TLC00000.AVI -vframes 1 first.jpeg    
ffmpeg -sseof -2 -i TLC00000.AVI -update 1 -q:v 1 last.jpg
    


  


  However, when I start looping them over several files in a directory I am starting to run into problems.

  


  SET "source=C:\Users\...\...\%%~nF"
SET "first=C:\Users\...\...\first%%~nF"
SET "last=C:\Users\...\...\last\%%~nF"

for %%F in (*.AVI) do (
    If not Exist source MkDir first
    ffmpeg -i %%F -vframes 1 first\%%~nF-%%3d.first.jpg)

for %%F in (*.AVI) do (
    If not Exist source MkDir last
    ffmpeg -sseof -2 -i %%F -update 1 -q:v 1 last\%%~nF-%%3d.last.jpg)
Pause


  


  Any help with how to make this loop working is warmly welcome.

  


• Save a stream of arrays to video using FFMPEG

  13 décembre 2022, par Gianluca Iacchini

  I made a simple fluid simulation using CUDA, and I'm trying to save it to a video using FFMPEG, however I get the Finishing stream 0:0 without any data written to it warning.

  


  This is how i send the data

  


  unsigned char* data = new unsigned char[SCR_WIDTH * SCR_HEIGHT * 4];
uchar4* pColors = new uchar4[SCR_WIDTH * SCR_HEIGHT];

for (int i = 0; i < N_FRAMES; i ++)
{
    // Computes a simulation step and sets pColors with the correct values.
    on_frame(pColors, timeStepSize);
    for (int j = 0; j < SCR_WIDTH * SCR_HEIGHT * 4; j+=4)
    {
        data[j] = pColors[j].x;
        data[j+1] = pColors[j].y;
        data[j+2] = pColors[j].z;
        data[j+3] = pColors[j].w;
    }
    std::cout.write(reinterpret_cast(data), SCR_WIDTH * SCR_HEIGHT * 4);
}


  


  And then I pass it to FFMPEG using the following command :

  


  ./simulation.o | ffmpeg -y -f rawvideo -pixel_format rgba -video_size 1024x1024 -i - -c:v libx264 -pix_fmt yuv444p -crf 0 video.mp4
`

  


  This works fine if I hard code the values (es. if I set data[j] = 255 I get a red screen as expected) but when I use the pColors variable I get the following message from FFMPEG

  


  Finishing stream 0:0 without any data written to it.

  


  Even though both pColors and data hold the correct values.

  


  Here is the full report from FFMPEG

  


  ffmpeg started on 2022-12-13 at 14:28:34
Report written to "ffmpeg-20221213-142834.log"
Command line:
ffmpeg -y -f rawvideo -report -pixel_format rgba -video_size 128x128 -i - -c:v libx264 -pix_fmt yuv444p -crf 0 video9.mp4
ffmpeg version 3.4.11-0ubuntu0.1 Copyright (c) 2000-2022 the FFmpeg developers
  built with gcc 7 (Ubuntu 7.5.0-3ubuntu1~18.04)
  configuration: --prefix=/usr --extra-version=0ubuntu0.1 --toolchain=hardened --libdir=/usr/lib/x86_64-linux-gnu --incdir=/usr/include/x86_64-linux-gnu --enable-gpl --disable-stripping --enable-avresample --enable-avisynth --enable-gnutls --enable-ladspa --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libcdio --enable-libflite --enable-libfontconfig --enable-libfreetype --enable-libfribidi --enable-libgme --enable-libgsm --enable-libmp3lame --enable-libmysofa --enable-libopenjpeg --enable-libopenmpt --enable-libopus --enable-libpulse --enable-librubberband --enable-librsvg --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libssh --enable-libtheora --enable-libtwolame --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx265 --enable-libxml2 --enable-libxvid --enable-libzmq --enable-libzvbi --enable-omx --enable-openal --enable-opengl --enable-sdl2 --enable-libdc1394 --enable-libdrm --enable-libiec61883 --enable-chrom  libavutil      55. 78.100 / 55. 78.100
  libavcodec     57.107.100 / 57.107.100
  libavformat    57. 83.100 / 57. 83.100
  libavdevice    57. 10.100 / 57. 10.100
  libavfilter     6.107.100 /  6.107.100
  libavresample   3.  7.  0 /  3.  7.  0
  libswscale      4.  8.100 /  4.  8.100
  libswresample   2.  9.100 /  2.  9.100
  libpostproc    54.  7.100 / 54.  7.100
Splitting the commandline.
Reading option '-y' ... matched as option 'y' (overwrite output files) with argument '1'.
Reading option '-f' ... matched as option 'f' (force format) with argument 'rawvideo'.
Reading option '-report' ... matched as option 'report' (generate a report) with argument '1'.
Reading option '-pixel_format' ... matched as AVOption 'pixel_format' with argument 'rgba'.
Reading option '-video_size' ... matched as AVOption 'video_size' with argument '128x128'.
Reading option '-i' ... matched as input url with argument '-'.
Reading option '-c:v' ... matched as option 'c' (codec name) with argument 'libx264'.
Reading option '-pix_fmt' ... matched as option 'pix_fmt' (set pixel format) with argument 'yuv444p'.
Reading option '-crf' ... matched as AVOption 'crf' with argument '0'.
Reading option 'video9.mp4' ... matched as output url.
Finished splitting the commandline.
Parsing a group of options: global .
Applying option y (overwrite output files) with argument 1.
Applying option report (generate a report) with argument 1.
Successfully parsed a group of options.
Parsing a group of options: input url -.
Applying option f (force format) with argument rawvideo.
Successfully parsed a group of options.
Opening an input file: -.
[rawvideo @ 0x558eba7b0000] Opening 'pipe:' for reading
[pipe @ 0x558eba78a080] Setting default whitelist 'crypto'
[rawvideo @ 0x558eba7b0000] Before avformat_find_stream_info() pos: 0 bytes read:0 seeks:0 nb_streams:1
[rawvideo @ 0x558eba7b0000] After avformat_find_stream_info() pos: 0 bytes read:0 seeks:0 frames:0
Input #0, rawvideo, from 'pipe:':
  Duration: N/A, bitrate: 13107 kb/s
    Stream #0:0, 0, 1/25: Video: rawvideo (RGBA / 0x41424752), rgba, 128x128, 13107 kb/s, 25 tbr, 25 tbn, 25 tbc
Successfully opened the file.
Parsing a group of options: output url video9.mp4.
Applying option c:v (codec name) with argument libx264.
Applying option pix_fmt (set pixel format) with argument yuv444p.
Successfully parsed a group of options.
Opening an output file: video9.mp4.
[file @ 0x558eba78a200] Setting default whitelist 'file,crypto'
Successfully opened the file.
Stream mapping:
  Stream #0:0 -> #0:0 (rawvideo (native) -> h264 (libx264))
cur_dts is invalid (this is harmless if it occurs once at the start per stream)
No more output streams to write to, finishing.
Finishing stream 0:0 without any data written to it.
detected 2 logical cores
[graph 0 input from stream 0:0 @ 0x558eba7a4a00] Setting 'video_size' to value '128x128'
[graph 0 input from stream 0:0 @ 0x558eba7a4a00] Setting 'pix_fmt' to value '28'
[graph 0 input from stream 0:0 @ 0x558eba7a4a00] Setting 'time_base' to value '1/25'
[graph 0 input from stream 0:0 @ 0x558eba7a4a00] Setting 'pixel_aspect' to value '0/1'
[graph 0 input from stream 0:0 @ 0x558eba7a4a00] Setting 'sws_param' to value 'flags=2'
[graph 0 input from stream 0:0 @ 0x558eba7a4a00] Setting 'frame_rate' to value '25/1'
[graph 0 input from stream 0:0 @ 0x558eba7a4a00] w:128 h:128 pixfmt:rgba tb:1/25 fr:25/1 sar:0/1 sws_param:flags=2
[format @ 0x558eba7a4b40] compat: called with args=[yuv444p]
[format @ 0x558eba7a4b40] Setting 'pix_fmts' to value 'yuv444p'
[auto_scaler_0 @ 0x558eba7a4be0] Setting 'flags' to value 'bicubic'
[auto_scaler_0 @ 0x558eba7a4be0] w:iw h:ih flags:'bicubic' interl:0
[format @ 0x558eba7a4b40] auto-inserting filter 'auto_scaler_0' between the filter 'Parsed_null_0' and the filter 'format'
[AVFilterGraph @ 0x558eba76d500] query_formats: 4 queried, 2 merged, 1 already done, 0 delayed
[auto_scaler_0 @ 0x558eba7a4be0] w:128 h:128 fmt:rgba sar:0/1 -> w:128 h:128 fmt:yuv444p sar:0/1 flags:0x4
[libx264 @ 0x558eba7cf900] using mv_range_thread = 24
[libx264 @ 0x558eba7cf900] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 AVX FMA3 BMI2 AVX2 AVX512
[libx264 @ 0x558eba7cf900] profile High 4:4:4 Predictive, level 1.1, 4:4:4 8-bit
[libx264 @ 0x558eba7cf900] 264 - core 152 r2854 e9a5903 - H.264/MPEG-4 AVC codec - Copyleft 2003-2017 - http://www.videolan.org/x264.html - options: cabac=1 ref=3 deblock=1:0:0 analyse=0x1:0x111 me=hex subme=7 psy=0 mixed_ref=1 me_range=16 chroma_me=1 trellis=0 8x8dct=0 cqm=0 deadzone=21,11 fast_pskip=0 chroma_qp_offset=0 threads=3 lookahead_threads=1 sliced_threads=0 nr=0 decimate=1 interlaced=0 bluray_compat=0 constrained_intra=0 bframes=0 weightp=2 keyint=250 keyint_min=25 scenecut=40 intra_refresh=0 rc=cqp mbtree=0 qp=0
Output #0, mp4, to 'video9.mp4':
  Metadata:
    encoder         : Lavf57.83.100
    Stream #0:0, 0, 1/12800: Video: h264 (libx264) (avc1 / 0x31637661), yuv444p, 128x128, q=-1--1, 25 fps, 12800 tbn, 25 tbc
    Metadata:
      encoder         : Lavc57.107.100 libx264
    Side data:
      cpb: bitrate max/min/avg: 0/0/0 buffer size: 0 vbv_delay: -1
frame=    0 fps=0.0 q=0.0 Lsize=       0kB time=00:00:00.00 bitrate=N/A speed=   0x    
video:0kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: unknown
Input file #0 (pipe:):
  Input stream #0:0 (video): 0 packets read (0 bytes); 0 frames decoded; 
  Total: 0 packets (0 bytes) demuxed
Output file #0 (video9.mp4):
  Output stream #0:0 (video): 0 frames encoded; 0 packets muxed (0 bytes); 
  Total: 0 packets (0 bytes) muxed
0 frames successfully decoded, 0 decoding errors
[AVIOContext @ 0x558eba7b4120] Statistics: 2 seeks, 3 writeouts
[AVIOContext @ 0x558eba7b4000] Statistics: 0 bytes read, 0 seeks



  


  I've never used FFMPEG before so I'm having a hard time finding my mistake.