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• FFPLAY produces black video output [closed]

  28 janvier 2020, par RooterTooter

  I’m having an issue playing videos with ffplay on an embedded arm device (imx6). The OS is based on yocto sumo and uses the meta-freescale layers for imx6.

  I have a number of test videos in different formats that I am sure are formatted correctly (They play fine on my laptop with ffplay). FFMPEG has all the necessary codecs, detects my streams, it plays audio without an issue, but the video is just black.

  It’s worth nothing that I’m running X11 and have xterm running, and when ffplay is trying to play, a black box will pop up on the screen in the correct dimensions like it thinks it’s decoding video, but it’s always blank.

  $DISPLAY=:0 ffplay test.mp4
  
  ffplay version 3.3.3 Copyright (c) 2003-2017 the FFmpeg developers
  
    built with gcc 7.3.0 (GCC)
  
    configuration: --disable-stripping --enable-pic --enable-shared --enable-pthreads --disable-libxcb --disable-libxcb-shm --disable-libxcb-xfixes --disable-libxcb-shape --enable-nonfree --cross-prefix=arm-poky-linux-gnueabi- --ld='arm-poky-linux-gnueabi-gcc -march=armv7-a -mfpu=neon -mfloat-abi=hard -mcpu=cortex-a9 --sysroot=/home/builder/imx-yocto-bsp/machine/tmp/work/cortexa9hf-neon-poky-linux-gnueabi/ffmpeg/3.3.3-r0/recipe-sysroot' --cc='arm-poky-linux-gnueabi-gcc -march=armv7-a -mfpu=neon -mfloat-abi=hard -mcpu=cortex-a9 --sysroot=/home/builder/imx-yocto-bsp/machine/tmp/work/cortexa9hf-neon-poky-linux-gnueabi/ffmpeg/3.3.3-r0/recipe-sysroot' --cxx='arm-poky-linux-gnueabi-g++ -march=armv7-a -mfpu=neon -mfloat-abi=hard -mcpu=cortex-a9 --sysroot=/home/builder/imx-yocto-bsp/machine/tmp/work/cortexa9hf-neon-poky-linux-gnueabi/ffmpeg/3.3.3-r0/recipe-sysroot' --arch=arm --target-os=linux --enable-cross-compile --extra-cflags=' -O2 -pipe -g -feliminate-unused-debug-types -fdebug-prefix-map=/home/builder/imx-yocto-bsp/machine/tmp/work/cortexa9hf-neon-poky-linux-gnueabi/ffmpeg/3.3.3-r0=/usr/src/debug/ffmpeg/3.3.3-r0 -fdebug-prefix-map=/home/builder/imx-yocto-bsp/machine/tmp/work/cortexa9hf-neon-poky-linux-gnueabi/ffmpeg/3.3.3-r0/recipe-sysroot-native= -fdebug-prefix-map=/home/builder/imx-yocto-bsp/machine/tmp/work/cortexa9hf-neon-poky-linux-gnueabi/ffmpeg/3.3.3-r0/recipe-sysroot= -march=armv7-a -mfpu=neon -mfloat-abi=hard -mcpu=cortex-a9 --sysroot=/home/builder/imx-yocto-bsp/machine/tmp/work/cortexa9hf-neon-poky-linux-gnueabi/ffmpeg/3.3.3-r0/recipe-sysroot' --extra-ldflags='-Wl,-O1 -Wl,--hash-style=gnu -Wl,--as-needed' --sysroot=/home/builder/imx-yocto-bsp/machine/tmp/work/cortexa9hf-neon-poky-linux-gnueabi/ffmpeg/3.3.3-r0/recipe-sysroot --enable-hardcoded-tables --libdir=/usr/lib --shlibdir=/usr/lib --datadir=/usr/share/ffmpeg --disable-mipsdsp --disable-mipsdspr2 --cpu=cortex-a9 --pkg-config=pkg-config --enable-avcodec --enable-avdevice --enable-avfilter --enable-avformat --enable-avresample --enable-bzlib --enable-gpl --disable-libgsm --disable-indev=jack --disable-libvorbis --enable-lzma --disable-libmp3lame --enable-openssl --enable-postproc --disable-libschroedinger --enable-sdl2 --disable-libspeex --enable-swresample --enable-swscale --enable-libtheora --enable-vaapi --enable-vdpau --enable-libvpx --enable-libx264 --enable-outdev=xv
  
    libavutil      55. 58.100 / 55. 58.100
  
    libavcodec     57. 89.100 / 57. 89.100
  
    libavformat    57. 71.100 / 57. 71.100
  
    libavdevice    57.  6.100 / 57.  6.100
  
    libavfilter     6. 82.100 /  6. 82.100
  
    libavresample   3.  5.  0 /  3.  5.  0
  
    libswscale      4.  6.100 /  4.  6.100
  
    libswresample   2.  7.100 /  2.  7.100
  
    libpostproc    54.  5.100 / 54.  5.100
  
  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'test.mp4':q=    0B f=0/0   
  
    Metadata:
  
      major_brand     : isom
  
      minor_version   : 512
  
      compatible_brands: isomiso2avc1mp41
  
      encoder         : Lavf58.20.100
  
    Duration: 00:00:30.88, start: 0.000000, bitrate: 143 kb/s
  
      Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 320x180, 67 kb/s, 21.08 fps, 21.08 tbr, 16192 tbn, 42.17 tbc (default)
  
      Metadata:
  
        handler_name    : VideoHandler
  
      Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, mono, fltp, 66 kb/s (default)
  
      Metadata:
  
        handler_name    : SoundHandler

  I’ve tried h264 and mp2 video with the same results. Has anyone seen this before

• Remove some redundant NULL checks and fix a free on error return.

  3 mars 2012, par Tim Terriberry

  Remove some redundant NULL checks and fix a free on error return.
  ref_frame_data was being allocated with the aligned allocator, but
  
   freed with the normal _ogg_free() function on failure, which
  
   doesn’t work.
  
  This would only cause a problem if there was just enough memory to
  
   satisfy the reference frame allocation (just over 4.5 or 9 bytes
  
   per pixel) but not enough for the fragment buffer offets (1/16 or
  
   1/8th byte per pixel).
  git-svn-id : http://svn.xiph.org/trunk/theora@18219 0101bb08-14d6-0310-b084-bc0e0c8e3800
  

  • [DH] lib/internal.c
  • [DH] lib/state.c

• Exception thrown at 0x00007FFC0B57BCEF (swscale-6.dll) in App.exe : 0xC0000005 : Access violation reading location 0xFFFFFFFFFFFFFFFF

  9 novembre 2023, par JIUN-YU

  Trying to play a video using FFmpeg on visual studio 2022 on windows 10.
Exception is thrown at sws_scale in the code. Don't know why this is occurred.
It is worth noting that this error sometimes occurs when reading the camera and sometimes it does not.

  


  here is my code

  


  bool CalibrationPanel::video_reader_read_frame(VReaderState* state, cv::Mat cvimg)
{
    // Unpack members of state
    auto& width = state->width;
    auto& height = state->height;
    auto& av_format_ctx = state->av_format_ctx;
    auto& av_codec_ctx = state->av_codec_ctx;
    auto& video_stream_index = state->video_stream_index;
    auto& av_frame = state->av_frame;
    auto& av_packet = state->av_packet;
    auto& sws_scaler_ctx = state->sws_scaler_ctx;


    // Decode one frame
    int response;
    while (av_read_frame(av_format_ctx, av_packet) >= 0)
    {
        if (av_packet->stream_index != video_stream_index)
        {
            av_packet_unref(av_packet);
            continue;
        }

        response = avcodec_send_packet(av_codec_ctx, av_packet);
        if (response < 0)
        {
            char errStr[256] = {0};
            av_strerror(response, errStr, sizeof(errStr));
            printf("Failed to decode packet: %s\n", errStr);
            return false;
        }

        response = avcodec_receive_frame(av_codec_ctx, av_frame);
        if (response == AVERROR(EAGAIN) || response == AVERROR_EOF)
        {
            av_packet_unref(av_packet);
            continue;
        }
        else if (response < 0)
        {
            char errStr[256] = {0};
            av_strerror(response, errStr, sizeof(errStr));
            printf("Failed to decode packet: %s\n", errStr);
            return false;
        }

        av_packet_unref(av_packet);
        break;
    }
    int64_t* pts = &ppts;
    *pts = av_frame->pts;

    // Set up sws scaler
    if (!sws_scaler_ctx)
    {
        sws_scaler_ctx = sws_getContext(width, height, av_codec_ctx->pix_fmt,
                                        width, height, AV_PIX_FMT_BGR24,
                                        SWS_BILINEAR, NULL, NULL, NULL);
        if (!sws_scaler_ctx)
        {
            printf("Couldn't initialize sw scaler\n");
            return false;
        }
    }


    // Creating an image space to hold YUV images
    AVFrame* frameYUV = av_frame_alloc();
    auto* out_buffer = (unsigned char*)av_malloc(av_image_get_buffer_size(AV_PIX_FMT_BGR24, width, height, 1));
    av_image_fill_arrays(frameYUV->data, frameYUV->linesize, (const uint8_t*)out_buffer, AV_PIX_FMT_BGR24, width, height, 1);

    uint8_t* dest[4] = {cvimg.data, NULL, NULL, NULL};
    sws_scale(sws_scaler_ctx, av_frame->data, av_frame->linesize, 0, av_frame->height, dest, frameYUV->linesize);

    return true;
}


  


  fixed this bug, so it's not luck that makes the camera turn on every time.