Opencv 4.10 Can't Decode Webp from Memory

[jsl303]

Python 3.7.3
opencv-python 4.1.0.25 from pip install opencv-python
I can open and write webp format from file with no problem, but I can't decode from memory. The code (at the end) returns:

imdecode_(''): can't read data: OpenCV(4.1.0) /io/opencv/modules/imgcodecs/src/grfmt_webp.cpp:164: error: (-215:Assertion failed) data.rows == 1 in function 'readData'
However, it works with opencv 3.4.2 from conda install opencv.
Also, Kaggle kernel environment (Python 3.6.6 and opencv-python 4.1.0.25) just returns None object without throwing an error.

img = cv2.imread(file)
retval, buf = cv2.imencode(".webp", img, [cv2.IMWRITE_WEBP_QUALITY, 100])
img = cv2.imdecode(buf, 1)

[alalek]

Add dumps:

• cv.getBuildInformation()
• img.shape / cv.utils.dumpInputArray(img)
• retval
• buf.shape / cv.utils.dumpInputArray(buf)

[jsl303]

cv2.getBuildInformation: 
General configuration for OpenCV 4.1.0 =====================================
  Version control:               4.1.0

  Platform:
    Timestamp:                   2019-04-11T16:39:30Z
    Host:                        Linux 4.4.0-101-generic x86_64
    CMake:                       3.9.0
    CMake generator:             Unix Makefiles
    CMake build tool:            /usr/bin/gmake
    Configuration:               Release

  CPU/HW features:
    Baseline:                    SSE SSE2 SSE3
      requested:                 SSE3
    Dispatched code generation:  SSE4_1 SSE4_2 FP16 AVX AVX2
      requested:                 SSE4_1 SSE4_2 AVX FP16 AVX2 AVX512_SKX
      SSE4_1 (13 files):         + SSSE3 SSE4_1
      SSE4_2 (1 files):          + SSSE3 SSE4_1 POPCNT SSE4_2
      FP16 (0 files):            + SSSE3 SSE4_1 POPCNT SSE4_2 FP16 AVX
      AVX (4 files):             + SSSE3 SSE4_1 POPCNT SSE4_2 AVX
      AVX2 (27 files):           + SSSE3 SSE4_1 POPCNT SSE4_2 FP16 FMA3 AVX AVX2

  C/C++:
    Built as dynamic libs?:      NO
    C++ Compiler:                /usr/lib/ccache/compilers/c++  (ver 4.8.2)
    C++ flags (Release):         -Wl,-strip-all   -fsigned-char -W -Wall -Werror=return-type -Werror=non-virtual-dtor -Werror=address -Werror=sequence-point -Wformat -Werror=format-security -Wmissing-declarations -Wundef -Winit-self -Wpointer-arith -Wsign-promo -Wuninitialized -Winit-self -Wno-delete-non-virtual-dtor -Wno-comment -Wno-missing-field-initializers -fdiagnostics-show-option -Wno-long-long -pthread -fomit-frame-pointer -ffunction-sections -fdata-sections  -msse -msse2 -msse3 -fvisibility=hidden -fvisibility-inlines-hidden -O3 -DNDEBUG  -DNDEBUG
    C++ flags (Debug):           -Wl,-strip-all   -fsigned-char -W -Wall -Werror=return-type -Werror=non-virtual-dtor -Werror=address -Werror=sequence-point -Wformat -Werror=format-security -Wmissing-declarations -Wundef -Winit-self -Wpointer-arith -Wsign-promo -Wuninitialized -Winit-self -Wno-delete-non-virtual-dtor -Wno-comment -Wno-missing-field-initializers -fdiagnostics-show-option -Wno-long-long -pthread -fomit-frame-pointer -ffunction-sections -fdata-sections  -msse -msse2 -msse3 -fvisibility=hidden -fvisibility-inlines-hidden -g  -O0 -DDEBUG -D_DEBUG
    C Compiler:                  /usr/lib/ccache/compilers/cc
    C flags (Release):           -Wl,-strip-all   -fsigned-char -W -Wall -Werror=return-type -Werror=non-virtual-dtor -Werror=address -Werror=sequence-point -Wformat -Werror=format-security -Wmissing-declarations -Wmissing-prototypes -Wstrict-prototypes -Wundef -Winit-self -Wpointer-arith -Wuninitialized -Winit-self -Wno-comment -Wno-missing-field-initializers -fdiagnostics-show-option -Wno-long-long -pthread -fomit-frame-pointer -ffunction-sections -fdata-sections  -msse -msse2 -msse3 -fvisibility=hidden -O3 -DNDEBUG  -DNDEBUG
    C flags (Debug):             -Wl,-strip-all   -fsigned-char -W -Wall -Werror=return-type -Werror=non-virtual-dtor -Werror=address -Werror=sequence-point -Wformat -Werror=format-security -Wmissing-declarations -Wmissing-prototypes -Wstrict-prototypes -Wundef -Winit-self -Wpointer-arith -Wuninitialized -Winit-self -Wno-comment -Wno-missing-field-initializers -fdiagnostics-show-option -Wno-long-long -pthread -fomit-frame-pointer -ffunction-sections -fdata-sections  -msse -msse2 -msse3 -fvisibility=hidden -g  -O0 -DDEBUG -D_DEBUG
    Linker flags (Release):      -L/root/ffmpeg_build/lib  -Wl,--gc-sections  
    Linker flags (Debug):        -L/root/ffmpeg_build/lib  -Wl,--gc-sections  
    ccache:                      YES
    Precompiled headers:         NO
    Extra dependencies:          ade gthread-2.0 glib-2.0 /lib64/libz.so /opt/libjpeg-turbo/lib64/libjpeg.a dl m pthread rt
    3rdparty dependencies:       ittnotify libprotobuf libwebp libpng libtiff libjasper IlmImf quirc

  OpenCV modules:
    To be built:                 calib3d core dnn features2d flann gapi highgui imgcodecs imgproc ml objdetect photo python3 stitching video videoio
    Disabled:                    world
    Disabled by dependency:      -
    Unavailable:                 java js python2 ts
    Applications:                -
    Documentation:               NO
    Non-free algorithms:         NO

  GUI: 
    GTK+:                        NO
    VTK support:                 NO

  Media I/O: 
    ZLib:                        /lib64/libz.so (ver 1.2.3)
    JPEG:                        /opt/libjpeg-turbo/lib64/libjpeg.a (ver 62)
    WEBP:                        build (ver encoder: 0x020e)
    PNG:                         build (ver 1.6.36)
    TIFF:                        build (ver 42 - 4.0.10)
    JPEG 2000:                   build (ver 1.900.1)
    OpenEXR:                     build (ver 1.7.1)
    HDR:                         YES
    SUNRASTER:                   YES
    PXM:                         YES
    PFM:                         YES

  Video I/O:
    DC1394:                      NO
    FFMPEG:                      YES
      avcodec:                   YES (58.47.106)
      avformat:                  YES (58.26.101)
      avutil:                    YES (56.26.100)
      swscale:                   YES (5.4.100)
      avresample:                NO
    GStreamer:                   NO
    v4l/v4l2:                    YES (linux/videodev2.h)

  Parallel framework:            pthreads

  Trace:                         YES (with Intel ITT)

  Other third-party libraries:
    Lapack:                      NO
    Eigen:                       NO
    Custom HAL:                  NO
    Protobuf:                    build (3.5.1)

  OpenCL:                        YES (no extra features)
    Include path:                /io/opencv/3rdparty/include/opencl/1.2
    Link libraries:              Dynamic load

  Python 3:
    Interpreter:                 /opt/python/cp36-cp36m/bin/python (ver 3.6.8)
    Libraries:                   libpython3.6m.a (ver 3.6.8)
    numpy:                       /opt/python/cp36-cp36m/lib/python3.6/site-packages/numpy/core/include (ver 1.11.3)
    install path:                python

  Python (for build):            /opt/python/cp36-cp36m/bin/python

  Java:                          
    ant:                         NO
    JNI:                         NO
    Java wrappers:               NO
    Java tests:                  NO

  Install to:                    /io/_skbuild/linux-x86_64-3.6/cmake-install
-----------------------------------------------------------------


img = cv2.imread(file)
#img.shape: (400, 400, 3)
#cv2.utils.dumpInputArray InputArray: empty()=false kind=0x00010000 flags=0x01010000 total(-1)=160000 dims(-1)=2 size(-1)=400x400 type(-1)=CV_8UC3
retval, buf = cv2.imencode(".webp", img, [cv2.IMWRITE_WEBP_QUALITY, 100])
#retval: True
#buf.shape: (18546, 1)
#cv2.utils.dumpInputArray: InputArray: empty()=false kind=0x00010000 flags=0x01010000 total(-1)=18546 dims(-1)=2 size(-1)=1x18546 type(-1)=CV_8UC1
img = cv2.imdecode(buf, 1)
#imdecode_(''): can't read data: OpenCV(4.1.0) /io/opencv/modules/imgcodecs/src/grfmt_webp.cpp:164: error: (-215:Assertion failed) data.rows == 1 in function 'readData'
#type(img): <class 'NoneType'>

[skvark]

See also: https://answers.opencv.org/question/210682/cv2-imdecode-webp-format-fails/

[sunlightyxy]

Hi All,I also encountered this problem when calling opencv410 in Java,How can I solve this problem?thanks all

LOG:
imdecode_(''): can't read data: OpenCV(4.1.0) /home/yuxiaoyang/repo_test/xmss_3rdparty/opencv-4.1.0-imsize/modules/imgcodecs/src/grfmt_webp.cpp:164: error: (-215:Assertion failed) data.rows == 1 in function 'readData' imdecode width=0 imdecode height=0