opencv · 03kiko · Mar 24, 2025 · May 1, 2025 · May 1, 2025 · May 2, 2025
diff --git a/modules/videoio/src/cap_ffmpeg.cpp b/modules/videoio/src/cap_ffmpeg.cpp
@@ -194,7 +194,8 @@ class CvVideoWriter_FFMPEG_proxy CV_FINAL :
             }
         }
 
-        icvWriteFrame_FFMPEG_p(ffmpegWriter, (const uchar*)image.getMat().ptr(), (int)image.step(), image.cols(), image.rows(), image.channels(), 0);
+        if (!icvWriteFrame_FFMPEG_p(ffmpegWriter, (const uchar*)image.getMat().ptr(), (int)image.step(), image.cols(), image.rows(), image.channels(), 0))
+            CV_LOG_WARNING(NULL, "FFmpeg: Failed to write frame");
     }
     virtual bool open( const cv::String& filename, int fourcc, double fps, cv::Size frameSize, const VideoWriterParameters& params )
     {

diff --git a/modules/videoio/src/cap_ffmpeg_impl.hpp b/modules/videoio/src/cap_ffmpeg_impl.hpp
@@ -2525,11 +2525,13 @@ bool CvVideoWriter_FFMPEG::writeFrame( const unsigned char* data, int step, int
     // check parameters
     if (input_pix_fmt == AV_PIX_FMT_BGR24) {
         if (cn != 3) {
+            CV_LOG_WARNING(NULL, "write frame skipped - expected 3 channels but got " << cn);
             return false;
         }
     }
     else if (input_pix_fmt == AV_PIX_FMT_GRAY8 || input_pix_fmt == AV_PIX_FMT_GRAY16LE) {
         if (cn != 1) {
+            CV_LOG_WARNING(NULL, "write frame skipped - expected 1 channel but got " << cn);
             return false;
         }
     }
@@ -2640,14 +2642,16 @@ bool CvVideoWriter_FFMPEG::writeFrame( const unsigned char* data, int step, int
         }
         hw_frame->pts = frame_idx;
         int ret_write = icv_av_write_frame_FFMPEG(oc, video_st, context, outbuf, outbuf_size, hw_frame, frame_idx);
-        ret = ret_write >= 0 ? true : false;
+        // AVERROR(EAGAIN): continue sending input, not an error
+        ret = (ret_write >= 0 || ret_write == AVERROR(EAGAIN));
         av_frame_free(&hw_frame);
     } else
 #endif
     {
         picture->pts = frame_idx;
         int ret_write = icv_av_write_frame_FFMPEG(oc, video_st, context, outbuf, outbuf_size, picture, frame_idx);
-        ret = ret_write >= 0 ? true : false;
+        // AVERROR(EAGAIN): continue sending input, not an error
+        ret = (ret_write >= 0 || ret_write == AVERROR(EAGAIN));
     }
 
     frame_idx++;

diff --git a/modules/videoio/src/cap_gstreamer.cpp b/modules/videoio/src/cap_gstreamer.cpp
@@ -2699,7 +2699,7 @@ void CvVideoWriter_GStreamer::write(InputArray image)
     }
     else if (input_pix_fmt == GST_VIDEO_FORMAT_GRAY16_LE) {
         if (image.type() != CV_16UC1) {
-            CV_WARN("write frame skipped - expected CV_16UC3");
+            CV_WARN("write frame skipped - expected CV_16UC1");
             return;
         }
     }

diff --git a/modules/videoio/test/test_ffmpeg.cpp b/modules/videoio/test/test_ffmpeg.cpp
@@ -953,4 +953,81 @@ inline static std::string videoio_ffmpeg_16bit_name_printer(const testing::TestP
 
 INSTANTIATE_TEST_CASE_P(/**/, videoio_ffmpeg_16bit, testing::ValuesIn(sixteen_bit_modes), videoio_ffmpeg_16bit_name_printer);
 
+typedef tuple<int /*inputType*/, int /*Depth*/, bool /*isColor*/, bool /*isValid*/, string /*description*/> ChannelMismatchTestParams;
+typedef testing::TestWithParam< ChannelMismatchTestParams > videoio_ffmpeg_channel_mismatch;
+
+TEST_P(videoio_ffmpeg_channel_mismatch, basic)
+{
+    if (!videoio_registry::hasBackend(CAP_FFMPEG))
+        throw SkipTestException("FFmpeg backend was not found");
+
+    const string filename = "mismatch_video.mp4";
+    int input_type = get<0>(GetParam());
+    int depth = get<1>(GetParam());
+    bool is_Color = get<2>(GetParam());
+    bool is_valid = get<3>(GetParam());
+    const string description = get<4>(GetParam());
+
+    const double fps = 15.0;
+    const int fourcc = VideoWriter::fourcc('m', 'p', '4', 'v');
+    const Mat frame(480, 640, input_type, Scalar::all(0));
+
+    VideoWriter writer(filename, fourcc, fps, frame.size(),
+                                {
+                                    cv::VIDEOWRITER_PROP_DEPTH, depth,
+                                    VIDEOWRITER_PROP_IS_COLOR, is_Color
+                                });
+
+    if (!writer.isOpened())
+        throw SkipTestException("Failed to open video writer");
+
+    for (int i = 1; i <= 15; i++)
+    {
+        // In case of mismatch between input frame channels and
+        // expected depth/isColor configuration a warning  should be printed communicating it
+        writer.write(frame);
+    }
+
+    writer.release();
+
+    VideoCapture cap(filename, CAP_FFMPEG);
+
+    if (is_valid) {
+        ASSERT_TRUE(cap.isOpened()) << "Can't open video for " << description;
+        EXPECT_EQ(cap.get(CAP_PROP_FRAME_COUNT), 15) << "All frames should be written for: " << description;
+    } else {
+        ASSERT_FALSE(cap.isOpened()) << "Video capture should fail to open for: " << description;
+    }
+
+    std::remove(filename.c_str());
+}
+
+const ChannelMismatchTestParams mismatch_cases[] =
+{
+    // Testing input frame channels and expected depth/isColor combinations
+
+    // Open VideoWriter depth/isColor combination: CV_8U/true, everything with 3 channels should be valid
+    make_tuple(CV_16UC1, CV_8U, true, false, "input_CV_16UC1_expected_CV_8U_isColor_true"),
+    make_tuple(CV_8UC1, CV_8U, true, false, "input_CV_8UC1_expected_CV_8U_isColor_true"),
+    make_tuple(CV_8UC3, CV_8U, true, true, "input_CV_8UC3_expected_CV_8U_isColor_true_valid"),
+    make_tuple(CV_16UC3, CV_8U, true, true, "input_CV_16UC3_expected_CV_8U_isColor_true_valid"),
+
+    // Open VideoWriter depth/isColor combination: 16U,8U/false, everything with 1 channel should be valid
+    make_tuple(CV_8UC3, CV_8U, false, false, "input_CV_8UC3_expected_CV_8U_isColor_false"),
+    make_tuple(CV_16UC3, CV_8U, false, false, "input_CV_16UC3_expected_CV_8U_isColor_false"),
+    make_tuple(CV_8UC3, CV_16U, false, false, "input_CV_8UC3_expected_CV_16U_isColor_false"),
+    make_tuple(CV_16UC3, CV_16U, false, false, "input_CV_16UC3_expected_CV_16U_isColor_false"),
+    make_tuple(CV_8UC1, CV_16U, false, true, "input_CV_8UC1_expected_CV_16U_isColor_false_valid"),
+    make_tuple(CV_16UC1, CV_8U, false, true, "input_CV_16UC1_expected_CV_8U_isColor_false_valid"),
+};
+
+inline static std::string videoio_ffmpeg_mismatch_name_printer(const testing::TestParamInfo<videoio_ffmpeg_channel_mismatch::ParamType>& info)
+{
+    std::ostringstream os;
+    os << get<4>(info.param);
+    return os.str();
+}
+
+INSTANTIATE_TEST_CASE_P(/**/, videoio_ffmpeg_channel_mismatch, testing::ValuesIn(mismatch_cases), videoio_ffmpeg_mismatch_name_printer);
+
 }} // namespace