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• FFmpeg Hardware Acceleration with NVENC produces Half Green output video

  17 juin 2016, par Dan Sandland

  Using the FFmpeg build found here : https://github.com/illuspas/ffmpeg-hw-win32

  gcc 5.3.0
  
  --enable-nvenc nvidia_video_sdk_6.0.1
  
  --enable-libmfx Intel(R)_Media_SDK_2016.0.1
  
  --enable-libfdk-aac 0.1.4
  
  --enable-libspeex 1.2rc1
  
  --enable-libx264 1:148.20150725
  
  --enable-libopenh264 1.5.0
  
  --enable-libx265 1.8
  
  --enable-libopus 1.1.2
  
  --enable-libmp3lame 3.99.5
  
  --enable-libkvazaar 0.8.2

  ./configure —prefix=/home/aliang/FFmpeg/x86_64 —enable-small —disable-debug —disable-doc —arch=x86_64 —cc=’ccache x86_64-w64-mingw32-gcc’ —cross-prefix=x86_64-w64-mingw32- —enable-cross-compile —target-os=mingw32 —enable-libfdk-aac —enable-libmp3lame —enable-libopus —enable-libspeex —enable-libx264 —enable-libx265 —enable-libmfx —enable-nvenc —enable-libopenh264 —enable-libkvazaar —enable-gpl —enable-nonfree

  I’m running Windows on a MacBook Pro. I also tried with a more recent build and had the same output.

  Input video is from sample-videos.com.

  The ffmpeg command I am running is :

  ffmpeg -y -i sample.mp4 -vcodec nvenc_h264 -pixel_format yuv420p -f mp4 sample-out-nvenc.mp4

  sample-out-nvenc.mp4 looks like this via ffplay or vlc :

  

  When I grab a frame using jpeg2, the colors appear normal, but the height is squished.

  ffmpeg -y -ss 15.5 -i sample.mp4 -vframes 1 -s 480x300 -f image2 grab.jpg

  

  The ffprobe results for the output (sample-out-nvenc.mp4) :

  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'sample-out-nvenc.mp4':
  
    Metadata:
  
      major_brand     : isom
  
      minor_version   : 512
  
      compatible_brands: isomiso2avc1mp41
  
      encoder         : Lavf57.25.100
  
    Duration: 00:00:31.02, start: 0.021333, bitrate: 1994 kb/s
  
      Stream #0:0(und): Video: h264 (avc1 / 0x31637661), yuv420p(tv), 640x480 [SAR 1:1 DAR 4:3], 1650 kb/s, 25 fps, 25 tbr, 12800 tbn, 50 tbc (default)
  
      Metadata:
  
        handler_name    : VideoHandler
  
      Stream #0:1(und): Audio: aac (mp4a / 0x6134706D), 48000 Hz, 5.1, fltp, 342 kb/s (default)
  
      Metadata:
  
        handler_name    : SoundHandler

  Lastly the output from the nvenc encoding command :

  ffmpeg -y -i sample.mp4 -vcodec nvenc_h264 -pixel_format yuv420p -f mp4 sample-out-nvenc.mp4
  
  ffmpeg version 3.0 Copyright (c) 2000-2016 the FFmpeg developers
  
    built with gcc 5.3.0 (GCC)
  
    configuration: --prefix=/home/aliang/FFmpeg/x86_64 --enable-small --disable-debug --disable-doc --arch=x86_64 --cc='ccache x86_64-w64-mingw32-gcc' --cross-prefix=x86_64-w64-mingw32- --enable-cross-compile --target-os=mingw32 --enable-libfdk-aac --enable-libmp3lame --enable-libopus --enable-libspeex --enable-libx264 --enable-libx265 --enable-libmfx --enable-nvenc --enable-libopenh264 --enable-libkvazaar --enable-gpl --enable-nonfree
  
    libavutil      55. 17.103 / 55. 17.103
  
    libavcodec     57. 24.102 / 57. 24.102
  
    libavformat    57. 25.100 / 57. 25.100
  
    libavdevice    57.  0.101 / 57.  0.101
  
    libavfilter     6. 31.100 /  6. 31.100
  
    libswscale      4.  0.100 /  4.  0.100
  
    libswresample   2.  0.101 /  2.  0.101
  
    libpostproc    54.  0.100 / 54.  0.100
  
  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'sample.mp4':
  
    Metadata:
  
      major_brand     : isom
  
      minor_version   : 512
  
      compatible_brands: isomiso2avc1mp41
  
      creation_time   : 1970-01-01 00:00:00
  
      encoder         : Lavf53.24.2
  
    Duration: 00:00:31.00, start: 0.000000, bitrate: 1353 kb/s
  
      Stream #0:0(und): Video: h264 (avc1 / 0x31637661), yuv420p, 640x480 [SAR 1:1 DAR 4:3], 966 kb/s, 25 fps, 25 tbr, 12800 tbn, 50 tbc (default)
  
      Metadata:
  
        creation_time   : 1970-01-01 00:00:00
  
        handler_name    : VideoHandler
  
      Stream #0:1(und): Audio: aac (mp4a / 0x6134706D), 48000 Hz, 5.1, fltp, 383 kb/s (default)
  
      Metadata:
  
        creation_time   : 1970-01-01 00:00:00
  
        handler_name    : SoundHandler
  
  Output #0, mp4, to 'sample-out-nvenc.mp4':
  
    Metadata:
  
      major_brand     : isom
  
      minor_version   : 512
  
      compatible_brands: isomiso2avc1mp41
  
      encoder         : Lavf57.25.100
  
      Stream #0:0(und): Video: h264 (nvenc_h264) ([33][0][0][0] / 0x0021), yuv420p, 640x480 [SAR 1:1 DAR 4:3], q=-1--1, 2000 kb/s, 25 fps, 12800 tbn, 25 tbc (default)
  
      Metadata:
  
        creation_time   : 1970-01-01 00:00:00
  
        handler_name    : VideoHandler
  
        encoder         : Lavc57.24.102 nvenc_h264
  
      Side data:
  
        unknown side data type 10 (24 bytes)
  
      Stream #0:1(und): Audio: aac ([64][0][0][0] / 0x0040), 48000 Hz, 5.1, fltp, 341 kb/s (default)
  
      Metadata:
  
        creation_time   : 1970-01-01 00:00:00
  
        handler_name    : SoundHandler
  
        encoder         : Lavc57.24.102 aac
  
  Stream mapping:
  
    Stream #0:0 -> #0:0 (h264 (native) -> h264 (nvenc_h264))
  
    Stream #0:1 -> #0:1 (aac (native) -> aac (native))
  
  Press [q] to stop, [?] for help
  
  frame=  774 fps=253 q=-0.0 Lsize=    7551kB time=00:00:30.99 bitrate=1995.6kbits/s speed=10.1x
  
  video:6236kB audio:1297kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 0.243011%
  
  [aac @ 000001cdd9900520] Qavg: 743.457

• Rotating a video during encoding with ffmpeg and libav API results in half of video corrupted

  11 mai 2020, par Daniel Kobe

  I'm using the C API for ffmpeg/libav to rotate a vertically filmed iphone video during the encoding step. There are other questions asking to do a similar thing but they are all using the CLI tool to do so.

  



  So far I was able to figure out how to use the AVFilter to rotate the video, base off this example https://github.com/FFmpeg/FFmpeg/blob/master/doc/examples/filtering_video.c

  



  The problem is that half the output file is corrupt.


  



  Here is the code for my encoding logic. Its written with GOLANG using CGO to interface with the C API.

  



  // Encode encode an AVFrame and return it
func Encode(enc Encoder, frame *C.AVFrame) (*EncodedFrame, error) {
    ctx := enc.Context()

    if ctx.buffersrcctx == nil {
        // initialize filter
        outputs := C.avfilter_inout_alloc()
        inputs  := C.avfilter_inout_alloc()
        m_pFilterGraph := C.avfilter_graph_alloc()
        buffersrc := C.avfilter_get_by_name(C.CString("buffer"))
        argsStr := fmt.Sprintf("video_size=%dx%d:pix_fmt=%d:time_base=%d/%d:pixel_aspect=%d/%d", ctx.avctx.width, ctx.avctx.height, ctx.avctx.pix_fmt, ctx.avctx.time_base.num, ctx.avctx.time_base.den, ctx.avctx.sample_aspect_ratio.num, ctx.avctx.sample_aspect_ratio.den)
        Log.Info.Println("yakotest")
        Log.Info.Println(argsStr)
        args := C.CString(argsStr)
        ret := C.avfilter_graph_create_filter(&ctx.buffersrcctx, buffersrc, C.CString("my_buffersrc"), args, nil, m_pFilterGraph)
        if ret < 0 {
            Log.Info.Printf("\n problem creating filter %v\n", AVError(ret).Error())
        }

        buffersink := C.avfilter_get_by_name(C.CString("buffersink"))
        ret = C.avfilter_graph_create_filter(&ctx.buffersinkctx, buffersink, C.CString("my_buffersink"), nil, nil, m_pFilterGraph)
        if ret < 0 {
            Log.Info.Printf("\n problem creating filter %v\n", AVError(ret).Error())
        }

        /*
         * Set the endpoints for the filter graph. The filter_graph will
         * be linked to the graph described by filters_descr.
         */

        /*
         * The buffer source output must be connected to the input pad of
         * the first filter described by filters_descr; since the first
         * filter input label is not specified, it is set to "in" by
         * default.
         */
        outputs.name       = C.av_strdup(C.CString("in"))
        outputs.filter_ctx = ctx.buffersrcctx
        outputs.pad_idx    = 0
        outputs.next       = nil

        /*
         * The buffer sink input must be connected to the output pad of
         * the last filter described by filters_descr; since the last
         * filter output label is not specified, it is set to "out" by
         * default.
         */
        inputs.name       = C.av_strdup(C.CString("out"))
        inputs.filter_ctx = ctx.buffersinkctx
        inputs.pad_idx    = 0
        inputs.next       = nil

        ret = C.avfilter_graph_parse_ptr(m_pFilterGraph, C.CString("transpose=clock,scale=-2:1080"),
            &inputs, &outputs, nil)
        if ret < 0 {
            Log.Info.Printf("\n problem with avfilter_graph_parse %v\n", AVError(ret).Error())
        }

        ret = C.avfilter_graph_config(m_pFilterGraph, nil)
        if ret < 0 {
            Log.Info.Printf("\n problem with graph config %v\n", AVError(ret).Error())
        }
    }

    filteredFrame :=  C.av_frame_alloc()

    /* push the decoded frame into the filtergraph */
    ret := C.av_buffersrc_add_frame_flags(ctx.buffersrcctx, frame, C.AV_BUFFERSRC_FLAG_KEEP_REF)
    if ret < 0 {
        Log.Error.Printf("\nError while feeding the filter greaph, err = %v\n", AVError(ret).Error())
        return nil, errors.New(ErrorFFmpegCodecFailure)
    }

    /* pull filtered frames from the filtergraph */
    for {
        ret = C.av_buffersink_get_frame(ctx.buffersinkctx, filteredFrame)
        if ret == C.AVERROR_EAGAIN || ret == C.AVERROR_EOF {
            break
        }
        if ret < 0 {
            Log.Error.Printf("\nCouldnt find a frame, err = %v\n", AVError(ret).Error())
            return nil, errors.New(ErrorFFmpegCodecFailure)
        }

        filteredFrame.pts = frame.pts
        frame = filteredFrame
        defer C.av_frame_free(&filteredFrame)
    }

    if frame != nil {
        frame.pict_type = 0 // reset pict type for the encoder
        if C.avcodec_send_frame(ctx.avctx, frame) != 0 {
            Log.Error.Printf("%+v\n", StackErrorf("codec error, could not send frame"))
            return nil, errors.New(ErrorFFmpegCodecFailure)
        }
    }

    for {
        ret := C.avcodec_receive_packet(ctx.avctx, ctx.pkt)
        if ret == C.AVERROR_EAGAIN {
            break
        }
        if ret == C.AVERROR_EOF {
            return nil, fmt.Errorf("EOF")
        }
        if ret < 0 {
            Log.Error.Printf("%+v\n", StackErrorf("codec error, receiving packet"))
            return nil, errors.New(ErrorFFmpegCodecFailure)
        }

        data := C.GoBytes(unsafe.Pointer(ctx.pkt.data), ctx.pkt.size)
        return &EncodedFrame{data, int64(ctx.pkt.pts), int64(ctx.pkt.dts),
            (ctx.pkt.flags & C.AV_PKT_FLAG_KEY) != 0}, nil
    }

    return nil, nil
}


  



  It seems like I need to do something with the scaling here but I'm struggling to find helpful information online.

  


• avformat/aviobuf : Improve readability of aviobuf (Add comments and docs)

  16 novembre 2015, par Bryan Huh

  avformat/aviobuf : Improve readability of aviobuf (Add comments and docs)
  Signed-off-by : Michael Niedermayer <michael@niedermayer.cc>
  

  • [DH] libavformat/avio.h
  • [DH] libavformat/aviobuf.c