OpenCVでテキストオーバーレイでビデオを保存する

Question

私のウェブカメラからビデオを録画し、その上にテキストを書き込んでディスクに保存するスクリプトを作成しました。しかし、私はVLCで再生するビデオやビデオを再生することはできません。

ここで、私は実行するすべてのコーデック/拡張タイプの組み合わせを、しようとするスクリプトだのVLCで動作するかどうかを確認、繰り返しEscキーを押すと、スクリプトが終了するまで、組み合わせごとに繰り返します。

import cv2 
import os 

extensions = ['avi', 'mp4'] 
codecs = ['MJPG', 'H264', 'DIVX', 'XVID', 'X264'] 

for ext in extensions: 
    for codec in codecs: 
     savepath = "output__%s.%s" % (codec, ext) 

     try: 
      # setup up our webcam to read frames 
      cap = cv2.VideoCapture(0) 
      cap.set(cv2.CAP_PROP_FRAME_WIDTH, 1920) 
      cap.set(cv2.CAP_PROP_FRAME_HEIGHT, 1080) 

      # and our buffer to write frames 
      fourcc = cv2.VideoWriter_fourcc(*codec) 
      out = cv2.VideoWriter(savepath, fourcc, 20.0, (1080, 1920), 1) 

      while True: 
       ret, frame = cap.read() 
       text = 'testing 123' 
       font = cv2.FONT_HERSHEY_SIMPLEX 
       cv2.putText(frame, text, (50, 50), font, 2, (255, 255, 0), 2) 

       # write our frame 
       out.write(frame) 

       cv2.imshow('My Frame', frame) 
       ch = cv2.waitKey(1) 
       if ch == 27: # ESC 
        break 


      cap.release() 
      out.release() 
      cv2.destroyAllWindows() 

      os.system("vlc %s" % savepath) 

     except Exception as e: 
      print "Combo codec=%s, exte=%s failed with: %s" % (codec, ext, str(e)) 

結果はこのスクリプト実行するので：

$ python test.py 
OpenCV Error: Assertion failed (img.cols == width && img.rows == height && channels == 3) in write, file /home/me/code/myproject/OpenCV-3.2.0/modules/videoio/src/cap_mjpeg_encoder.cpp, line 829 
Combo codec=MJPG, exte=avi failed with: /home/me/code/myproject/OpenCV-3.2.0/modules/videoio/src/cap_mjpeg_encoder.cpp:829: error: (-215) img.cols == width && img.rows == height && channels == 3 in function write 

VIDEOIO ERROR: V4L2: Pixel format of incoming image is unsupported by OpenCV 
Unable to stop the stream: Device or resource busy 
OpenCV Error: Assertion failed (size.width>0 && size.height>0) in imshow, file /home/me/code/myproject/OpenCV-3.2.0/modules/highgui/src/window.cpp, line 312 
Combo codec=H264, exte=avi failed with: /home/me/code/myproject/OpenCV-3.2.0/modules/highgui/src/window.cpp:312: error: (-215) size.width>0 && size.height>0 in function imshow 

init done 
opengl support available 

For codec=DIVX, extension=avi 
VLC media player 2.2.2 Weatherwax (revision 2.2.2-0-g6259d80) 
[0000000001f0e148] core libvlc: Running vlc with the default interface. Use 'cvlc' to use vlc without interface. 
[00007eff1cc017d8] avi demux error: no key frame set for track 0 
QObject::~QObject: Timers cannot be stopped from another thread 

For codec=XVID, extension=avi 
VLC media player 2.2.2 Weatherwax (revision 2.2.2-0-g6259d80) 
[00000000022b8148] core libvlc: Running vlc with the default interface. Use 'cvlc' to use vlc without interface. 
[00007f9c14c017d8] avi demux error: no key frame set for track 0 
QObject::~QObject: Timers cannot be stopped from another thread 

For codec=X264, extension=avi 
VLC media player 2.2.2 Weatherwax (revision 2.2.2-0-g6259d80) 
[0000000001a55148] core libvlc: Running vlc with the default interface. Use 'cvlc' to use vlc without interface. 
[00007f485cc017d8] avi demux error: no key frame set for track 0 
QObject::~QObject: Timers cannot be stopped from another thread 
OpenCV: FFMPEG: tag 0x47504a4d/'MJPG' is not supported with codec id 8 and format 'mp4/MP4 (MPEG-4 Part 14)' 
OpenCV: FFMPEG: fallback to use tag 0x0000006c/'l???' 

For codec=MJPG, extension=mp4 
VLC media player 2.2.2 Weatherwax (revision 2.2.2-0-g6259d80) 
[0000000000e53148] core libvlc: Running vlc with the default interface. Use 'cvlc' to use vlc without interface. 
[00007f02a8c017d8] mp4 demux error: cannot find any /moov/trak 
QObject::~QObject: Timers cannot be stopped from another thread 
OpenCV: FFMPEG: tag 0x34363248/'H264' is not supported with codec id 28 and format 'mp4/MP4 (MPEG-4 Part 14)' 
OpenCV: FFMPEG: fallback to use tag 0x00000021/'!???' 

For codec=H264, extension=mp4 
VLC media player 2.2.2 Weatherwax (revision 2.2.2-0-g6259d80) 
[00000000015f8148] core libvlc: Running vlc with the default interface. Use 'cvlc' to use vlc without interface. 
[00007f6994c01838] mp4 demux error: cannot find any /moov/trak 
QObject::~QObject: Timers cannot be stopped from another thread 
OpenCV: FFMPEG: tag 0x58564944/'DIVX' is not supported with codec id 13 and format 'mp4/MP4 (MPEG-4 Part 14)' 
OpenCV: FFMPEG: fallback to use tag 0x00000020/' ???' 

For codec=DIVX, extension=mp4 
VLC media player 2.2.2 Weatherwax (revision 2.2.2-0-g6259d80) 
[0000000001880148] core libvlc: Running vlc with the default interface. Use 'cvlc' to use vlc without interface. 
[00007f21acc017d8] mp4 demux error: cannot find any /moov/trak 
QObject::~QObject: Timers cannot be stopped from another thread 
OpenCV: FFMPEG: tag 0x44495658/'XVID' is not supported with codec id 13 and format 'mp4/MP4 (MPEG-4 Part 14)' 
OpenCV: FFMPEG: fallback to use tag 0x00000020/' ???' 

For codec=XVID, extension=mp4 
VLC media player 2.2.2 Weatherwax (revision 2.2.2-0-g6259d80) 
[000000000178c148] core libvlc: Running vlc with the default interface. Use 'cvlc' to use vlc without interface. 
[00007f1e64c01858] mp4 demux error: cannot find any /moov/trak 
QObject::~QObject: Timers cannot be stopped from another thread 
OpenCV: FFMPEG: tag 0x34363258/'X264' is not supported with codec id 28 and format 'mp4/MP4 (MPEG-4 Part 14)' 
OpenCV: FFMPEG: fallback to use tag 0x00000021/'!???' 

For codec=X264, extension=mp4 
VLC media player 2.2.2 Weatherwax (revision 2.2.2-0-g6259d80) 
[0000000000baa148] core libvlc: Running vlc with the default interface. Use 'cvlc' to use vlc without interface. 
[00007fdcc8c01838] mp4 demux error: cannot find any /moov/trak 
QObject::~QObject: Timers cannot be stopped from another thread 

を私は拡張子（.AVI、.MP4）とコーデックのすべての組み合わせを試してみました（MJPG、DIVX、XVID、H264）やビデオのどれもがプレイ可能です。

何が悪いと思いますか？

Answer 1

説明の後にhttps://github.com/ContinuumIO/anaconda-issues/issues/223。 jeremy-rutmanの提案を採用しました。「私は出力ビデオの寸法を入力フレームの寸法と同じに保つことでこれを解決できました。

次のコードは私のために働いた、私はint(cap.get(3))int(cap.get(4))のフレームサイズを使用します。 （私のapiも4cc検索のように少し異なります）、またwaitKeyは私のためには機能しませんので、100までループします。

import cv2 
import os 

extensions = ['avi','mp4'] 
codecs = ['MJPG','H264', 'DIVX', 'XVID', 'X264'] 

for ext in extensions: 
    for codec in codecs: 
     savepath = "output__%s.%s" % (codec, ext) 
     print savepath 
     try:   
      cap = cv2.VideoCapture(0) 

      # and our buffer to write frames 
      fourcc = cv2.cv.CV_FOURCC(*codec) 
      out = cv2.VideoWriter(savepath, fourcc, 20.0,  (int(cap.get(3)),int(cap.get(4))), 1) 
      i = 0; 
      while i < 100: 
       i = i +1 

       ret, frame = cap.read() 
       if not ret: 
        continue 

       text = 'testing 123' 
       font = cv2.FONT_HERSHEY_SIMPLEX 
       cv2.putText(frame, text, (50, 50), font, 2, (255, 255, 0), 2) 

       #write our frame 
       out.write(frame) 

       cv2.imshow('My Frame', frame) 
       ch = cv2.waitKey(1) 
       if ch == 27: # ESC 
        break 

      cap.release() 
      out.release() 
      cv2.destroyAllWindows() 

      os.system("vlc %s" % savepath) 

    except Exception as e: 
     print "Combo codec=%s, exte=%s failed with: %s" % (codec, ext, str(e))