Cannot capture and save video using OpenCV in macOS-CodePudding

I'm trying to use OpenCV to capture and create a video from my webcam, following the example that OpenCV provide in its website (See Saving a Video section).

So, my code is given below:

import numpy as np
import cv2 as cv
cap = cv.VideoCapture(0)
# Define the codec and create VideoWriter object
fourcc = cv.VideoWriter_fourcc('m','p','4','v')
out = cv.VideoWriter('output.mp4', fourcc, 20.0, (640,  480))
while cap.isOpened():
    ret, frame = cap.read()
    if not ret:
        print("Can't receive frame (stream end?). Exiting ...")
        break
    # write the flipped frame
    out.write(frame)
    cv.imshow('frame', frame)
    if cv.waitKey(1) == ord('q'):
        break
# Release everything if job is finished
cap.release()
out.release()
cv.destroyAllWindows()

For some reason, the generated video file (named output.mp4) is corrupt, because I can not play the video using video players. I can see the video in a windows but the output is corrupted.

I have checked the codecs available in my local just passing -1 like: out = cv.VideoWriter('output.mp4', -1, 20.0, (640, 480)), and I got the following:

OpenCV: FFMPEG: format avi / AVI (Audio Video Interleaved)
fourcc tag 0x34363248/'H264' codec_id 001B
fourcc tag 0x34363268/'h264' codec_id 001B
fourcc tag 0x34363258/'X264' codec_id 001B
fourcc tag 0x34363278/'x264' codec_id 001B
fourcc tag 0x31637661/'avc1' codec_id 001B
fourcc tag 0x43564144/'DAVC' codec_id 001B
fourcc tag 0x32564d53/'SMV2' codec_id 001B
fourcc tag 0x48535356/'VSSH' codec_id 001B
fourcc tag 0x34363251/'Q264' codec_id 001B
fourcc tag 0x34363256/'V264' codec_id 001B
fourcc tag 0x43564147/'GAVC' codec_id 001B
fourcc tag 0x56534d55/'UMSV' codec_id 001B
fourcc tag 0x64687374/'tshd' codec_id 001B
fourcc tag 0x434d4e49/'INMC' codec_id 001B
fourcc tag 0x33363248/'H263' codec_id 0004
fourcc tag 0x33363258/'X263' codec_id 0004
fourcc tag 0x33363254/'T263' codec_id 0004
fourcc tag 0x3336324c/'L263' codec_id 0004
fourcc tag 0x4b315856/'VX1K' codec_id 0004
fourcc tag 0x6f47795a/'ZyGo' codec_id 0004
fourcc tag 0x3336324d/'M263' codec_id 0004
fourcc tag 0x6d76736c/'lsvm' codec_id 0004
fourcc tag 0x33363248/'H263' codec_id 0013
fourcc tag 0x33363249/'I263' codec_id 0014
fourcc tag 0x31363248/'H261' codec_id 0003
fourcc tag 0x33363255/'U263' codec_id 0004
fourcc tag 0x344d5356/'VSM4' codec_id 0004
fourcc tag 0x34504d46/'FMP4' codec_id 000C
fourcc tag 0x58564944/'DIVX' codec_id 000C
fourcc tag 0x30355844/'DX50' codec_id 000C
fourcc tag 0x44495658/'XVID' codec_id 000C
fourcc tag 0x5334504d/'MP4S' codec_id 000C
fourcc tag 0x3253344d/'M4S2' codec_id 000C
fourcc tag 0x00000004/'????' codec_id 000C
fourcc tag 0x34504d5a/'ZMP4' codec_id 000C
fourcc tag 0x31564944/'DIV1' codec_id 000C
fourcc tag 0x305a4c42/'BLZ0' codec_id 000C
fourcc tag 0x7634706d/'mp4v' codec_id 000C
fourcc tag 0x34504d55/'UMP4' codec_id 000C
fourcc tag 0x46315657/'WV1F' codec_id 000C
fourcc tag 0x47444553/'SEDG' codec_id 000C
fourcc tag 0x34504d52/'RMP4' codec_id 000C
fourcc tag 0x32564933/'3IV2' codec_id 000C
fourcc tag 0x56574157/'WAWV' codec_id 000C
fourcc tag 0x53444646/'FFDS' codec_id 000C
fourcc tag 0x57465646/'FVFW' codec_id 000C
fourcc tag 0x444f4344/'DCOD' codec_id 000C
fourcc tag 0x4d58564d/'MVXM' codec_id 000C
fourcc tag 0x56344d50/'PM4V' codec_id 000C
fourcc tag 0x34504d53/'SMP4' codec_id 000C
fourcc tag 0x4d475844/'DXGM' codec_id 000C
fourcc tag 0x4d444956/'VIDM' codec_id 000C
fourcc tag 0x3354344d/'M4T3' codec_id 000C
fourcc tag 0x584f4547/'GEOX' codec_id 000C
fourcc tag 0x34363247/'G264' codec_id 000C
fourcc tag 0x34584448/'HDX4' codec_id 000C
fourcc tag 0x56344d44/'DM4V' codec_id 000C
fourcc tag 0x324b4d44/'DMK2' codec_id 000C
fourcc tag 0x344d5944/'DYM4' codec_id 000C
fourcc tag 0x49474944/'DIGI' codec_id 000C
fourcc tag 0x56485045/'EPHV' codec_id 000C
fourcc tag 0x41344d45/'EM4A' codec_id 000C
fourcc tag 0x4343344d/'M4CC' codec_id 000C
fourcc tag 0x30344e53/'SN40' codec_id 000C
fourcc tag 0x58505356/'VSPX' codec_id 000C
fourcc tag 0x58444c55/'ULDX' codec_id 000C
fourcc tag 0x564f4547/'GEOV' codec_id 000C
fourcc tag 0x50504953/'SIPP' codec_id 000C
fourcc tag 0x56344d53/'SM4V' codec_id 000C
fourcc tag 0x58495658/'XVIX' codec_id 000C
fourcc tag 0x58657244/'DreX' codec_id 000C
fourcc tag 0x34504d51/'QMP4' codec_id 000C
fourcc tag 0x31564c50/'PLV1' codec_id 000C
fourcc tag 0x34564c47/'GLV4' codec_id 000C
fourcc tag 0x34504d47/'GMP4' codec_id 000C
fourcc tag 0x344d4e4d/'MNM4' codec_id 000C
fourcc tag 0x344d5447/'GTM4' codec_id 000C
fourcc tag 0x3334504d/'MP43' codec_id 0010
fourcc tag 0x33564944/'DIV3' codec_id 0010
fourcc tag 0x3347504d/'MPG3' codec_id 0010
fourcc tag 0x35564944/'DIV5' codec_id 0010
fourcc tag 0x36564944/'DIV6' codec_id 0010
fourcc tag 0x34564944/'DIV4' codec_id 0010
fourcc tag 0x33585644/'DVX3' codec_id 0010
fourcc tag 0x31345041/'AP41' codec_id 0010
fourcc tag 0x314c4f43/'COL1' codec_id 0010
fourcc tag 0x304c4f43/'COL0' codec_id 0010
fourcc tag 0x3234504d/'MP42' codec_id 000F
fourcc tag 0x32564944/'DIV2' codec_id 000F
fourcc tag 0x3447504d/'MPG4' codec_id 000E
fourcc tag 0x3134504d/'MP41' codec_id 000E
fourcc tag 0x31564d57/'WMV1' codec_id 0011
fourcc tag 0x32564d57/'WMV2' codec_id 0012
fourcc tag 0x45565847/'GXVE' codec_id 0012
fourcc tag 0x64737664/'dvsd' codec_id 0018
fourcc tag 0x64687664/'dvhd' codec_id 0018
fourcc tag 0x31687664/'dvh1' codec_id 0018
fourcc tag 0x6c737664/'dvsl' codec_id 0018
fourcc tag 0x35327664/'dv25' codec_id 0018
fourcc tag 0x30357664/'dv50' codec_id 0018
fourcc tag 0x63766463/'cdvc' codec_id 0018
fourcc tag 0x48564443/'CDVH' codec_id 0018
fourcc tag 0x35564443/'CDV5' codec_id 0018
fourcc tag 0x20637664/'dvc ' codec_id 0018
fourcc tag 0x73637664/'dvcs' codec_id 0018
fourcc tag 0x31687664/'dvh1' codec_id 0018
fourcc tag 0x73697664/'dvis' codec_id 0018
fourcc tag 0x63766470/'pdvc' codec_id 0018
fourcc tag 0x35324c53/'SL25' codec_id 0018
fourcc tag 0x56444c53/'SLDV' codec_id 0018
fourcc tag 0x31645641/'AVd1' codec_id 0018
fourcc tag 0x3167706d/'mpg1' codec_id 0001
fourcc tag 0x3267706d/'mpg2' codec_id 0002
fourcc tag 0x4745504d/'MPEG' codec_id 0002
fourcc tag 0x314d4950/'PIM1' codec_id 0001
fourcc tag 0x324d4950/'PIM2' codec_id 0002
fourcc tag 0x32524356/'VCR2' codec_id 0001
fourcc tag 0x10000001/'????' codec_id 0001
fourcc tag 0x10000002/'????' codec_id 0002
fourcc tag 0x10000004/'????' codec_id 000C
fourcc tag 0x20525644/'DVR ' codec_id 0002
fourcc tag 0x53454d4d/'MMES' codec_id 0002
fourcc tag 0x32504d4c/'LMP2' codec_id 0002
fourcc tag 0x66696c73/'slif' codec_id 0002
fourcc tag 0x56324d45/'EM2V' codec_id 0002
fourcc tag 0x3130374d/'M701' codec_id 0002
fourcc tag 0x3230374d/'M702' codec_id 0002
fourcc tag 0x3330374d/'M703' codec_id 0002
fourcc tag 0x3430374d/'M704' codec_id 0002
fourcc tag 0x3530374d/'M705' codec_id 0002
fourcc tag 0x7667706d/'mpgv' codec_id 0002
fourcc tag 0x30315742/'BW10' codec_id 0001
fourcc tag 0x47504d58/'XMPG' codec_id 0001
fourcc tag 0x47504a4d/'MJPG' codec_id 0007
fourcc tag 0x3243534d/'MSC2' codec_id 0007
fourcc tag 0x47504a4c/'LJPG' codec_id 0007
fourcc tag 0x31626d64/'dmb1' codec_id 0007
fourcc tag 0x61706a6d/'mjpa' codec_id 0007
fourcc tag 0x3432524a/'JR24' codec_id 0007
fourcc tag 0x47504a4c/'LJPG' codec_id 0009
fourcc tag 0x4c47504a/'JPGL' codec_id 0007
fourcc tag 0x534c4a4d/'MJLS' codec_id 000B
fourcc tag 0x47504a4d/'MJPG' codec_id 000B
fourcc tag 0x534c4a4d/'MJLS' codec_id 0007
fourcc tag 0x6765706a/'jpeg' codec_id 0007
fourcc tag 0x47504a49/'IJPG' codec_id 0007
fourcc tag 0x6e525641/'AVRn' codec_id 8009
fourcc tag 0x56444341/'ACDV' codec_id 0007
fourcc tag 0x47564951/'QIVG' codec_id 0007
fourcc tag 0x4a4d4c53/'SLMJ' codec_id 0007
fourcc tag 0x47504a43/'CJPG' codec_id 0007
fourcc tag 0x564c4a49/'IJLV' codec_id 0007
fourcc tag 0x504a564d/'MVJP' codec_id 0007
fourcc tag 0x31495641/'AVI1' codec_id 0007
fourcc tag 0x32495641/'AVI2' codec_id 0007
fourcc tag 0x4a53544d/'MTSJ' codec_id 0007
fourcc tag 0x47504a5a/'ZJPG' codec_id 0007
fourcc tag 0x504a4d4d/'MMJP' codec_id 0007
fourcc tag 0x55594648/'HFYU' codec_id 0019
fourcc tag 0x48564646/'FFVH' codec_id 0043
fourcc tag 0x56555943/'CYUV' codec_id 001A
fourcc tag 0x00000000/'????' codec_id 000D
fourcc tag 0x00000003/'????' codec_id 000D
fourcc tag 0x30323449/'I420' codec_id 000D
fourcc tag 0x32595559/'YUY2' codec_id 000D
fourcc tag 0x32323459/'Y422' codec_id 000D
fourcc tag 0x32323456/'V422' codec_id 000D
fourcc tag 0x564e5559/'YUNV' codec_id 000D
fourcc tag 0x564e5955/'UYNV' codec_id 000D
fourcc tag 0x594e5955/'UYNY' codec_id 000D
fourcc tag 0x31767975/'uyv1' codec_id 000D
fourcc tag 0x31755632/'2Vu1' codec_id 000D
fourcc tag 0x79757632/'2vuy' codec_id 000D
fourcc tag 0x73767579/'yuvs' codec_id 000D
fourcc tag 0x32767579/'yuv2' codec_id 000D
fourcc tag 0x32323450/'P422' codec_id 000D
fourcc tag 0x32315659/'YV12' codec_id 000D
fourcc tag 0x36315659/'YV16' codec_id 000D
fourcc tag 0x34325659/'YV24' codec_id 000D
fourcc tag 0x59565955/'UYVY' codec_id 000D
fourcc tag 0x59555956/'VYUY' codec_id 000D
fourcc tag 0x56555949/'IYUV' codec_id 000D
fourcc tag 0x30303859/'Y800' codec_id 000D
fourcc tag 0x20203859/'Y8  ' codec_id 000D
fourcc tag 0x43594448/'HDYC' codec_id 000D
fourcc tag 0x39555659/'YVU9' codec_id 000D
fourcc tag 0x5a544456/'VDTZ' codec_id 000D
fourcc tag 0x31313459/'Y411' codec_id 000D
fourcc tag 0x3231564e/'NV12' codec_id 000D
fourcc tag 0x3132564e/'NV21' codec_id 000D
fourcc tag 0x42313459/'Y41B' codec_id 000D
fourcc tag 0x42323459/'Y42B' codec_id 000D
fourcc tag 0x39565559/'YUV9' codec_id 000D
fourcc tag 0x39555659/'YVU9' codec_id 000D
fourcc tag 0x32767561/'auv2' codec_id 000D
fourcc tag 0x55595659/'YVYU' codec_id 000D
fourcc tag 0x56595559/'YUYV' codec_id 000D
fourcc tag 0x30313449/'I410' codec_id 000D
fourcc tag 0x31313449/'I411' codec_id 000D
fourcc tag 0x32323449/'I422' codec_id 000D
fourcc tag 0x30343449/'I440' codec_id 000D
fourcc tag 0x34343449/'I444' codec_id 000D
fourcc tag 0x3032344a/'J420' codec_id 000D
fourcc tag 0x3232344a/'J422' codec_id 000D
fourcc tag 0x3034344a/'J440' codec_id 000D
fourcc tag 0x3434344a/'J444' codec_id 000D
fourcc tag 0x41565559/'YUVA' codec_id 000D
fourcc tag 0x41303449/'I40A' codec_id 000D
fourcc tag 0x41323449/'I42A' codec_id 000D
fourcc tag 0x32424752/'RGB2' codec_id 000D
fourcc tag 0x35315652/'RV15' codec_id 000D
fourcc tag 0x36315652/'RV16' codec_id 000D
fourcc tag 0x34325652/'RV24' codec_id 000D
fourcc tag 0x32335652/'RV32' codec_id 000D
fourcc tag 0x41424752/'RGBA' codec_id 000D
fourcc tag 0x32335641/'AV32' codec_id 000D
fourcc tag 0x59455247/'GREY' codec_id 000D
fourcc tag 0x4c393049/'I09L' codec_id 000D
fourcc tag 0x42393049/'I09B' codec_id 000D
fourcc tag 0x4c393249/'I29L' codec_id 000D
fourcc tag 0x42393249/'I29B' codec_id 000D
fourcc tag 0x4c393449/'I49L' codec_id 000D
fourcc tag 0x42393449/'I49B' codec_id 000D
fourcc tag 0x4c413049/'I0AL' codec_id 000D
fourcc tag 0x42413049/'I0AB' codec_id 000D
fourcc tag 0x4c413249/'I2AL' codec_id 000D
fourcc tag 0x42413249/'I2AB' codec_id 000D
fourcc tag 0x4c413449/'I4AL' codec_id 000D
fourcc tag 0x42413449/'I4AB' codec_id 000D
fourcc tag 0x4c463449/'I4FL' codec_id 000D
fourcc tag 0x42463449/'I4FB' codec_id 000D
fourcc tag 0x4c433049/'I0CL' codec_id 000D
fourcc tag 0x42433049/'I0CB' codec_id 000D
fourcc tag 0x4c433249/'I2CL' codec_id 000D
fourcc tag 0x42433249/'I2CB' codec_id 000D
fourcc tag 0x4c433449/'I4CL' codec_id 000D
fourcc tag 0x42433449/'I4CB' codec_id 000D
fourcc tag 0x4c463049/'I0FL' codec_id 000D
fourcc tag 0x42463049/'I0FB' codec_id 000D
fourcc tag 0x55575246/'FRWU' codec_id 0082
fourcc tag 0x6b303152/'R10k' codec_id 0090
fourcc tag 0x30313272/'r210' codec_id 0085
fourcc tag 0x30313276/'v210' codec_id 007F
fourcc tag 0x30313243/'C210' codec_id 007F
fourcc tag 0x38303376/'v308' codec_id 8006
fourcc tag 0x38303476/'v408' codec_id 8007
fourcc tag 0x56555941/'AYUV' codec_id 8004
fourcc tag 0x30313476/'v410' codec_id 009C
fourcc tag 0x34767579/'yuv4' codec_id 8008
fourcc tag 0x31335649/'IV31' codec_id 001C
fourcc tag 0x32335649/'IV32' codec_id 001C
fourcc tag 0x31345649/'IV41' codec_id 006F
fourcc tag 0x30355649/'IV50' codec_id 0070
fourcc tag 0x31335056/'VP31' codec_id 001D
fourcc tag 0x30335056/'VP30' codec_id 001D
fourcc tag 0x30345056/'VP40' codec_id 802D
fourcc tag 0x30355056/'VP50' codec_id 005A
fourcc tag 0x30365056/'VP60' codec_id 005B
fourcc tag 0x31365056/'VP61' codec_id 005B
fourcc tag 0x32365056/'VP62' codec_id 005B
fourcc tag 0x41365056/'VP6A' codec_id 006A
fourcc tag 0x46365056/'VP6F' codec_id 005C
fourcc tag 0x34564c46/'FLV4' codec_id 005C
fourcc tag 0x30375056/'VP70' codec_id 00B3
fourcc tag 0x31375056/'VP71' codec_id 00B3
fourcc tag 0x30385056/'VP80' codec_id 008B
fourcc tag 0x30395056/'VP90' codec_id 00A7
fourcc tag 0x31565341/'ASV1' codec_id 001F
fourcc tag 0x32565341/'ASV2' codec_id 0020
fourcc tag 0x31524356/'VCR1' codec_id 0023
fourcc tag 0x31564646/'FFV1' codec_id 0021
fourcc tag 0x6e617858/'Xxan' codec_id 0029
fourcc tag 0x30324d4c/'LM20' codec_id 0071
fourcc tag 0x656c726d/'mrle' codec_id 002D
fourcc tag 0x00000001/'????' codec_id 002D
fourcc tag 0x00000002/'????' codec_id 002D
fourcc tag 0x4356534d/'MSVC' codec_id 002E
fourcc tag 0x6376736d/'msvc' codec_id 002E
fourcc tag 0x4d415243/'CRAM' codec_id 002E
fourcc tag 0x6d617263/'cram' codec_id 002E
fourcc tag 0x4d414857/'WHAM' codec_id 002E
fourcc tag 0x6d616877/'wham' codec_id 002E
fourcc tag 0x64697663/'cvid' codec_id 002B
fourcc tag 0x4b435544/'DUCK' codec_id 0033
fourcc tag 0x5a455650/'PVEZ' codec_id 0033
fourcc tag 0x485a534d/'MSZH' codec_id 0035
fourcc tag 0x42494c5a/'ZLIB' codec_id 0036
fourcc tag 0x574f4e53/'SNOW' codec_id 800C
fourcc tag 0x564d5834/'4XMV' codec_id 0022
fourcc tag 0x31564c46/'FLV1' codec_id 0015
fourcc tag 0x33363253/'S263' codec_id 0015
fourcc tag 0x31565346/'FSV1' codec_id 0056
fourcc tag 0x31717673/'svq1' codec_id 0016
fourcc tag 0x63637374/'tscc' codec_id 0038
fourcc tag 0x49544c55/'ULTI' codec_id 0039
fourcc tag 0x4c584956/'VIXL' codec_id 003B
fourcc tag 0x47455051/'QPEG' codec_id 003C
fourcc tag 0x302e3151/'Q1.0' codec_id 003C
fourcc tag 0x312e3151/'Q1.1' codec_id 003C
fourcc tag 0x33564d57/'WMV3' codec_id 0047
fourcc tag 0x50564d57/'WMVP' codec_id 0096
fourcc tag 0x31435657/'WVC1' codec_id 0046
fourcc tag 0x41564d57/'WMVA' codec_id 0046
fourcc tag 0x32505657/'WVP2' codec_id 0097
fourcc tag 0x4f434f4c/'LOCO' codec_id 0048
fourcc tag 0x31564e57/'WNV1' codec_id 0049
fourcc tag 0x38565559/'YUV8' codec_id 0049
fourcc tag 0x34534141/'AAS4' codec_id 004A
fourcc tag 0x43534141/'AASC' codec_id 004A
fourcc tag 0x31325452/'RT21' codec_id 004B
fourcc tag 0x31535046/'FPS1' codec_id 004C
fourcc tag 0x6f656874/'theo' codec_id 001E
fourcc tag 0x30324d54/'TM20' codec_id 004D
fourcc tag 0x30325254/'TR20' codec_id 8011
fourcc tag 0x44435343/'CSCD' codec_id 004F
fourcc tag 0x56424d5a/'ZMBV' codec_id 0051
fourcc tag 0x43564d4b/'KMVC' codec_id 0055
fourcc tag 0x53564143/'CAVS' codec_id 0057
fourcc tag 0x32535641/'AVS2' codec_id 00C0
fourcc tag 0x32706a6d/'mjp2' codec_id 0058
fourcc tag 0x43324a4d/'MJ2C' codec_id 0058
fourcc tag 0x43324a4c/'LJ2C' codec_id 0058
fourcc tag 0x4b324a4c/'LJ2K' codec_id 0058
fourcc tag 0x324a5049/'IPJ2' codec_id 0058
fourcc tag 0x326a5641/'AVj2' codec_id 0058
fourcc tag 0x636e4d56/'VMnc' codec_id 0059
fourcc tag 0x20616774/'tga ' codec_id 005D
fourcc tag 0x474e504d/'MPNG' codec_id 003D
fourcc tag 0x31474e50/'PNG1' codec_id 003D
fourcc tag 0x20676e70/'png ' codec_id 003D
fourcc tag 0x524a4c43/'CLJR' codec_id 0024
fourcc tag 0x63617264/'drac' codec_id 0074
fourcc tag 0x72707a61/'azpr' codec_id 002A
fourcc tag 0x415a5052/'RPZA' codec_id 002A
fourcc tag 0x617a7072/'rpza' codec_id 002A
fourcc tag 0x34355053/'SP54' codec_id 000A
fourcc tag 0x41525541/'AURA' codec_id 007B
fourcc tag 0x32525541/'AUR2' codec_id 007C
fourcc tag 0x20787064/'dpx ' codec_id 0080
fourcc tag 0x3156474b/'KGV1' codec_id 0089
fourcc tag 0x5347414c/'LAGS' codec_id 0092
fourcc tag 0x46564d41/'AMVF' codec_id 006B
fourcc tag 0x41524c55/'ULRA' codec_id 0098
fourcc tag 0x47524c55/'ULRG' codec_id 0098
fourcc tag 0x30594c55/'ULY0' codec_id 0098
fourcc tag 0x32594c55/'ULY2' codec_id 0098
fourcc tag 0x34594c55/'ULY4' codec_id 0098
fourcc tag 0x30484c55/'ULH0' codec_id 0098
fourcc tag 0x32484c55/'ULH2' codec_id 0098
fourcc tag 0x34484c55/'ULH4' codec_id 0098
fourcc tag 0x30595155/'UQY0' codec_id 0098
fourcc tag 0x32595155/'UQY2' codec_id 0098
fourcc tag 0x41525155/'UQRA' codec_id 0098
fourcc tag 0x47525155/'UQRG' codec_id 0098
fourcc tag 0x32594d55/'UMY2' codec_id 0098
fourcc tag 0x32484d55/'UMH2' codec_id 0098
fourcc tag 0x34594d55/'UMY4' codec_id 0098
fourcc tag 0x34484d55/'UMH4' codec_id 0098
fourcc tag 0x41524d55/'UMRA' codec_id 0098
fourcc tag 0x47524d55/'UMRG' codec_id 0098
fourcc tag 0x454c4256/'VBLE' codec_id 009A
fourcc tag 0x30333145/'E130' codec_id 00A9
fourcc tag 0x726f7478/'xtor' codec_id 009B
fourcc tag 0x4f43455a/'ZECO' codec_id 00A0
fourcc tag 0x50313459/'Y41P' codec_id 8000
fourcc tag 0x434c4641/'AFLC' codec_id 0032
fourcc tag 0x3153534d/'MSS1' codec_id 00A1
fourcc tag 0x3141534d/'MSA1' codec_id 00A2
fourcc tag 0x32435354/'TSC2' codec_id 00A3
fourcc tag 0x3253544d/'MTS2' codec_id 00A4
fourcc tag 0x434c4c43/'CLLC' codec_id 00A5
fourcc tag 0x3253534d/'MSS2' codec_id 00A6
fourcc tag 0x33515653/'SVQ3' codec_id 0017
fourcc tag 0x76323130/'012v' codec_id 8002
fourcc tag 0x76323161/'a12v' codec_id 8002
fourcc tag 0x324d3247/'G2M2' codec_id 00AA
fourcc tag 0x334d3247/'G2M3' codec_id 00AA
fourcc tag 0x344d3247/'G2M4' codec_id 00AA
fourcc tag 0x354d3247/'G2M5' codec_id 00AA
fourcc tag 0x56434946/'FICV' codec_id 00AE
fourcc tag 0x58514843/'CHQX' codec_id 00B8
fourcc tag 0x43534454/'TDSC' codec_id 00B9
fourcc tag 0x43565543/'CUVC' codec_id 00BA
fourcc tag 0x30345652/'RV40' codec_id 0045
fourcc tag 0x31565053/'SPV1' codec_id 00BE
fourcc tag 0x43435352/'RSCC' codec_id 00BF
fourcc tag 0x43435349/'ISCC' codec_id 00BF
fourcc tag 0x44484643/'CFHD' codec_id 8010
fourcc tag 0x3130314d/'M101' codec_id 8012
fourcc tag 0x3230314d/'M102' codec_id 8012
fourcc tag 0x5947414d/'MAGY' codec_id 8013
fourcc tag 0x4752384d/'M8RG' codec_id 8013
fourcc tag 0x4152384d/'M8RA' codec_id 8013
fourcc tag 0x3047384d/'M8G0' codec_id 8013
fourcc tag 0x3059384d/'M8Y0' codec_id 8013
fourcc tag 0x3259384d/'M8Y2' codec_id 8013
fourcc tag 0x3459384d/'M8Y4' codec_id 8013
fourcc tag 0x4159384d/'M8YA' codec_id 8013
fourcc tag 0x4152304d/'M0RA' codec_id 8013
fourcc tag 0x4752304d/'M0RG' codec_id 8013
fourcc tag 0x3047304d/'M0G0' codec_id 8013
fourcc tag 0x3059304d/'M0Y0' codec_id 8013
fourcc tag 0x3259304d/'M0Y2' codec_id 8013
fourcc tag 0x3459304d/'M0Y4' codec_id 8013
fourcc tag 0x4152324d/'M2RA' codec_id 8013
fourcc tag 0x4752324d/'M2RG' codec_id 8013
fourcc tag 0x30434c59/'YLC0' codec_id 8015
fourcc tag 0x30514853/'SHQ0' codec_id 8018
fourcc tag 0x31514853/'SHQ1' codec_id 8018
fourcc tag 0x32514853/'SHQ2' codec_id 8018
fourcc tag 0x33514853/'SHQ3' codec_id 8018
fourcc tag 0x34514853/'SHQ4' codec_id 8018
fourcc tag 0x35514853/'SHQ5' codec_id 8018
fourcc tag 0x37514853/'SHQ7' codec_id 8018
fourcc tag 0x39514853/'SHQ9' codec_id 8018
fourcc tag 0x43564d46/'FMVC' codec_id 8019
fourcc tag 0x52504353/'SCPR' codec_id 801A
fourcc tag 0x444f4355/'UCOD' codec_id 801B
fourcc tag 0x31305641/'AV01' codec_id 801D
fourcc tag 0x4343534d/'MSCC' codec_id 801F
fourcc tag 0x43475253/'SRGC' codec_id 8020
fourcc tag 0x344d4d49/'IMM4' codec_id 8024
fourcc tag 0x30325442/'BT20' codec_id 8025
fourcc tag 0x4353574d/'MWSC' codec_id 8026
fourcc tag 0x564d4357/'WCMV' codec_id 8027
fourcc tag 0x43534152/'RASC' codec_id 8028
fourcc tag 0x544d5948/'HYMT' codec_id 8029
fourcc tag 0x43425241/'ARBC' codec_id 802A
fourcc tag 0x304d4741/'AGM0' codec_id 802B
fourcc tag 0x314d4741/'AGM1' codec_id 802B
fourcc tag 0x324d4741/'AGM2' codec_id 802B
fourcc tag 0x334d4741/'AGM3' codec_id 802B
fourcc tag 0x344d4741/'AGM4' codec_id 802B
fourcc tag 0x354d4741/'AGM5' codec_id 802B
fourcc tag 0x364d4741/'AGM6' codec_id 802B
fourcc tag 0x374d4741/'AGM7' codec_id 802B
fourcc tag 0x5243534c/'LSCR' codec_id 802C
fourcc tag 0x354d4d49/'IMM5' codec_id 802E
fourcc tag 0x5644564d/'MVDV' codec_id 802F
fourcc tag 0x4148564d/'MVHA' codec_id 8030
fourcc tag 0x3033564d/'MV30' codec_id 8032

Also, I got information from the generated video file with ffmpeg -i output.mp4 showing the following:

ffmpeg version 5.0.1 Copyright (c) 2000-2022 the FFmpeg developers
  built with Apple clang version 13.1.6 (clang-1316.0.21.2)
  configuration: --prefix=/usr/local/Cellar/ffmpeg/5.0.1 --enable-shared --enable-pthreads --enable-version3 --cc=clang --host-cflags= --host-ldflags= --enable-ffplay --enable-gnutls --enable-gpl --enable-libaom --enable-libbluray --enable-libdav1d --enable-libmp3lame --enable-libopus --enable-librav1e --enable-librist --enable-librubberband --enable-libsnappy --enable-libsrt --enable-libtesseract --enable-libtheora --enable-libvidstab --enable-libvmaf --enable-libvorbis --enable-libvpx --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxml2 --enable-libxvid --enable-lzma --enable-libfontconfig --enable-libfreetype --enable-frei0r --enable-libass --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-libspeex --enable-libsoxr --enable-libzmq --enable-libzimg --disable-libjack --disable-indev=jack --enable-videotoolbox
  libavutil      57. 17.100 / 57. 17.100
  libavcodec     59. 18.100 / 59. 18.100
  libavformat    59. 16.100 / 59. 16.100
  libavdevice    59.  4.100 / 59.  4.100
  libavfilter     8. 24.100 /  8. 24.100
  libswscale      6.  4.100 /  6.  4.100
  libswresample   4.  3.100 /  4.  3.100
  libpostproc    56.  3.100 / 56.  3.100
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'output.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2mp41
    encoder         : Lavf58.76.100
  Duration: 00:00:00.00, bitrate: N/A

Everything seem to be okay because I can execute the rest of the examples successfully.

I don't know how to fix it. I am using macOS 12.3.1, Python 3.10.2, numpy==1.22.3 and opencv-python==4.5.5.64.

CodePudding user response：

Can you try this to see if it work macos? I just added width and height.

import numpy as np
import cv2 as cv

cap = cv.VideoCapture(0)
# Define the codec and create VideoWriter object
width = int(cap.get(cv.CAP_PROP_FRAME_WIDTH)   0.5)
height = int(cap.get(cv.CAP_PROP_FRAME_HEIGHT)   0.5)
size = (width, height)

fourcc = cv.VideoWriter_fourcc(*'XVID')
out = cv.VideoWriter('output.avi', fourcc, 20.0, size)
while cap.isOpened():
    ret, frame = cap.read()
    if not ret:
        print("Can't receive frame (stream end?). Exiting ...")
        break
    # frame = cv.flip(frame, 0)
    # write the flipped frame
    out.write(frame)
    cv.imshow('frame', frame)
    if cv.waitKey(1) == ord('q'):
        break
# Release everything if job is finished
cap.release()
out.release()
cv.destroyAllWindows()

CodePudding user response：

It's a size problem.

import numpy as np
import cv2 as cv
cap = cv.VideoCapture(0)

size = (int(cap.get(cv.CAP_PROP_FRAME_WIDTH)),
        int(cap.get(cv.CAP_PROP_FRAME_HEIGHT)))

# Define the codec and create VideoWriter object
fourcc = cv.VideoWriter_fourcc(*"MP4V")
out = cv.VideoWriter('output.mp4', fourcc, 15, size)
while cap.isOpened():
    ret, frame = cap.read()
    if not ret:
        print("Can't receive frame (stream end?). Exiting ...")
        break
    # write the flipped frame
    out.write(frame)
    cv.imshow('frame', frame)
    if cv.waitKey(1) == ord('q'):
        break
# Release everything if job is finished
cap.release()
out.release()
cv.destroyAllWindows()

The code above worked fine for me.