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• Best intra-frame codec for editing ? Having color issues with DNxHR and serious sync issues with Prores

  23 janvier 2020, par Raulo1985

  I have a couple of questions regarding intra-frame codecs for editing purposes (in Premiere Pro).

  A LITTLE CONTEXT :

  I ripped a HDR movie to a MP4 container some months ago, using H.264 as codec (high 10, level 5, UHD, YUV, subsampling 4:2:0). The video looks great, as it should. Now I want to edit a trailer for that movie (I edit in Adobe Premiere Pro, current version), and for fast playback I need to work with proxies or transcode the source file to an intra-frame non long GOP file and use it as the source file (hopefully as lossless as that transcoding step can be). I tried for several days to transcode the source file to DNxHR 444 10 bits (using FFmpeg and then Adobe Media Encoder), but the result was always a video with the colors messed up (sometimes very washed out, sometimes over saturated).

  FFprobe of the resulting DNxHR file said that the color space was BT709 (source file is obviously BT2020), and I don’t know why. The transcoding involved upsampling since the source file is 4:2:0 and DNxHR doesn’t support it, but I tried upsampling to 4:4:4 and also to 4:2:2, and both of those files looked exactly the same to me, and very different from the original footage (so, I don’t think upsampling is the cause of the color issue, but maybe the apparent color space change or something wrong with the metadata). The results were the same when transcoding with Adobe Media Encoder. Anyway, I seem to have given up transcoding to DNxHR and use it as the source file, unless someone has an idea of what’s causing this problem. I could have worked with the source file for exporting and DNxHR LB for proxies, but there were sync issues (between source file and proxy) that defeated all purposes while editing. Prores is out of the picture, sync issues were worse (several seconds of delay).

  For the record, the command used that didn’t work as expected (color wise) is :

  ffmpeg -channel_layout 63 -i input.mkv -map 0:0 -c:v dnxhd -vf "scale=in_range=limited:out_range=full" -color_range 2 -profile:v dnxhr_444 -pix_fmt yuv444p10le -acodec pcm_s24le -ar 48000 -ac 6 -channel_layout 63 -map 0:2 -hide_banner output.mxf

  I also tried without the commands "scale=in_range=limited:out_range=full" and "-color_range 2", with same results. Always used FFmpeg latest version, and I’m working in Windows 10 Pro, latest drivers and latest Klite codec pack. Video files were compared with Mediainfo, FFprobe, and visually with VLC.

  Well, like I said, I’m giving up using DNxHR as the source file for my project (it would have been ideal since it doesn’t have sync issues with the DNxHR proxies, and file size is not a problem for me). A user here at the forums suggested transcoding and use H.264 intra-frame as source file, which I didn’t know was an option (I didn’t know H.264 was capable of intra-frame, my bad). I’m aware that one should avoid unnecesary transcoding steps, but I can’t work with a H.264 UHD HDR source file (ultra slow playback), and the sync issues with proxies, no matter the codec, make it impossible to make accurate cuts.
  So, bottom line, I need to find a way to fix the color issue when transcoding to DNxHR, or try with an inter-frame codec that’s not DNxHR and that’s capable of preserving all the HDR info (and then see if it doesn’t have sync issues. I’m assuming that those may dissapear when using intra-frame for both source file and proxies).

  NOTE : When importing the DNxHR 444 file to Premiere Pro and looking at the Lumetri scopes tab, you can tell that the colors are clipped at 100 nits, like a regular SDR video. So apparently the color space was really reduced to BT709, and I don’t know why. The H.264 source file behaves as expected, with colors going past 100 nits.

  MY QUESTIONS :

  1) Is H.264 intra-frame a good format for editing with a good playback performance ?

  2) If H.264 intra-frame is a good option, what would be the advantages of the DNxHR codec (or Prores) over it for editing purposes ? Everybody suggests DNxHD/DNxHR or Prores as intermediate codecs, but if intra-frame H.264 has the same advantages for editing and supports HDR, what would be the reason to choose another codec like DNxHR ?

  3) Any ideas on what could be the cause of the colors not transcoding correctly from the H.264 source file to the DNxHR 444 10 bits one ? The command looks ok to me, but FFprobe output says the DNxHR video is BT709, while with the source file it says BT2020. Like I said, apparently there’s something wrong with the transcoding process regarding metadata or color space.

  4) I haven’t tried to transcode the source file to a DNxHR 444 10 bits video file, but in a MOV container. I don’t know how this works internally, but maybe the color issue has something to do with the container metadata or something. I may try this if there’s not another suggestion (transcoding this kind of files, as you know, takes time, so I’ll wait for some ideas first).

  NOTE : I tried to transcode the source file in the same way (DNxHR 444, 10 bits, etc) with Adobe Media Encoder 2020 and the result was the same, with colors messed up and FFprobe saying the video is BT709. Also tried transcoding to DNxHR HQX profile (10 bits), same result.

  Any help would be greatly appreciated.

  Thanks in advance.

• ffserver leave original stream size

  28 novembre 2014, par ihnatkuk

  Hope you guys will help me, because I have got stuck and can’t find solution for this problem by myself.
  I am trying to stream video from webcam to users using ffmpeg+ffserver. But I have faced with a problem :

  ffmpeg gets stream from camera and pushes it to feed of ffserver:
  
  ffmpeg -rtsp_transport tcp -i rtsp://admin:admin@192.168.10.76:80 -y -vcodec libvpx http://127.0.0.1:8090/1.ffm

  ffserver stream options :

  <stream>
  
  Feed 1.ffm
  
  Format webm
  
  NoAudio
  
  #VideoCodec libvpx
  
  #VideoSize 480x320
  
  VideoFrameRate 24
  
  AVOptionVideo flags +global_header
  
  AVOptionVideo cpu-used 0
  
  AVOptionVideo qmin 1
  
  AVOptionVideo qmax 31
  
  AVOptionVideo quality good
  
  PreRoll 0
  
  StartSendOnKey
  
  VideoBitRate 128
  
  </stream>

  (note, videoSize option is commented). But even with default VideoSize (160x128), ffserver doesn’t respond for each request. Browser always gets :

  HTTP/1.0 200 OK
  
  Pragma: no-cache
  
  Content-Type: video/webm

  But sometimes video content is not sent.

  If I uncomment VideoSize option - the same problem but much less successfull requests comparing with default video size.

  ffserver log looks regular with no errors. But as you can see that sometimes it sends only headers to client :

  Thu Nov 27 12:49:11 2014 127.0.0.1 - - [POST] "/1.ffm HTTP/1.1" 200 459
  
  Thu Nov 27 12:49:25 2014 127.0.0.1 - - [POST] "/1.ffm HTTP/1.1" 200 459
  
  Thu Nov 27 12:49:36 2014 127.0.0.1 - - [POST] "/1.ffm HTTP/1.1" 200 459
  
  Thu Nov 27 12:50:52 2014 127.0.0.1 - - [POST] "/1.ffm HTTP/1.1" 200 459
  
  Thu Nov 27 12:53:54 2014 127.0.0.1 - - [POST] "/1.ffm HTTP/1.1" 200 459
  
  Thu Nov 27 13:30:19 2014 127.0.0.1 - - [GET] "/1.ffm HTTP/1.1" 200 4175
  
  Thu Nov 27 13:30:34 2014 127.0.0.1 - - [GET] "/1.webm HTTP/1.1" 200 385731
  
  Thu Nov 27 13:30:34 2014 127.0.0.1 - - [POST] "/1.ffm HTTP/1.1" 200 458752
  
  Thu Nov 27 13:30:36 2014 127.0.0.1 - - [GET] "/1.ffm HTTP/1.1" 200 4175
  
  Thu Nov 27 13:30:58 2014 127.0.0.1 - - [GET] "/1.webm HTTP/1.1" 200 493
  
  Thu Nov 27 13:30:58 2014 127.0.0.1 - - [POST] "/1.ffm HTTP/1.1" 200 622592

  Does anybody know what could it be ? Actually I need to save original VideoSize for stream. I am trying to override ffserver stream options with ffmpeg using the command (passing the same parameters as in ffserver’s stream) :

  ffmpeg -re -override_ffserver -rtsp_transport tcp -i rtsp://admin:admin@192.168.10.76:80 -an -r 24 -qmin 1 -qmax 31 -cpu-used 0 -quality good -flags:v +global_header -b:v 128 -vcodec libvpx -f webm -y http://127.0.0.1:8090/1.ffm

  But at the momment I still have error message ’Output file is empty, nothing was encoded’. Here is ffmpeg’s output :

  ffmpeg version 2.4.2 Copyright (c) 2000-2014 the FFmpeg developers
  
    built on Oct  6 2014 17:33:05 with gcc 4.8 (Ubuntu 4.8.2-19ubuntu1)
  
    configuration: --prefix=/opt/ffmpeg --libdir=/opt/ffmpeg/lib/ --enable-shared --enable-avresample --disable-stripping --enable-gpl --enable-version3 --enable-runtime-cpudetect --build-suffix=.ffmpeg --enable-postproc --enable-x11grab --enable-libcdio --enable-vaapi --enable-vdpau --enable-bzlib --enable-gnutls --enable-libgsm --enable-libschroedinger --enable-libspeex --enable-libtheora --enable-libvorbis --enable-libfaac --enable-libvo-aacenc --enable-nonfree --enable-libmp3lame --enable-libx264 --enable-libx265 --enable-libxvid --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libfdk_aac --enable-libopus --enable-pthreads --enable-zlib --enable-libvpx --enable-libfreetype --enable-libpulse --enable-debug=3
  
    libavutil      54.  7.100 / 54.  7.100
  
    libavcodec     56.  1.100 / 56.  1.100
  
    libavformat    56.  4.101 / 56.  4.101
  
    libavdevice    56.  0.100 / 56.  0.100
  
    libavfilter     5.  1.100 /  5.  1.100
  
    libavresample   2.  1.  0 /  2.  1.  0
  
    libswscale      3.  0.100 /  3.  0.100
  
    libswresample   1.  1.100 /  1.  1.100
  
    libpostproc    53.  0.100 / 53.  0.100
  
  Guessed Channel Layout for  Input Stream #0.1 : mono
  
  Input #0, rtsp, from 'rtsp://admin:admin@192.168.10.76:80':
  
    Metadata:
  
      title           : RTSP Session/2.0
  
    Duration: N/A, start: 0.000000, bitrate: 128 kb/s
  
      Stream #0:0: Video: h264 (High), yuvj420p(pc, bt709), 1280x720 [SAR 1:1 DAR 16:9], 25 fps, 100 tbr, 90k tbn, 50 tbc
  
      Stream #0:1: Audio: pcm_alaw, 16000 Hz, 1 channels, s16, 128 kb/s
  
  [swscaler @ 0x197f7a0] deprecated pixel format used, make sure you did set range correctly
  
  [libvpx @ 0x1a0c080] Bitrate 128 is extremely low, maybe you mean 128k
  
  [libvpx @ 0x1a0c080] v1.3.0
  
  The bitrate parameter is set too low. It takes bits/s as argument, not kbits/s
  
  Output #0, webm, to 'http://127.0.0.1:8090/1.ffm':
  
    Metadata:
  
      title           : RTSP Session/2.0
  
      encoder         : Lavf56.4.101
  
      Stream #0:0: Video: vp8 (libvpx), yuv420p, 480x320 [SAR 32:27 DAR 16:9], q=1-31, 0 kb/s, 24 fps, 1k tbn, 24 tbc
  
      Metadata:
  
        encoder         : Lavc56.1.100 libvpx
  
  Stream mapping:
  
    Stream #0:0 -> #0:0 (h264 (native) -> vp8 (libvpx))
  
  Press [q] to stop, [?] for help
  
  frame=   33 fps= 22 q=0.0 size=       0kB time=00:00:00.00 bitrate=N/A dup=0 droframe=   43 fps= 22 q=0.0 Lsize=       0kB time=00:00:00.00 bitrate=N/A dup=0 drop=1    
  
  video:0kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: unknown
  
  Output file is empty, nothing was encoded (check -ss / -t / -frames parameters if used)
  
  Received signal 2: terminating.

  Thanks in advance.

• Convert MP4 Version - FFmpeg

  17 mai 2017, par Luzwitz

  I have two mp4 File :

  1. out.mp4 : ISO Media, MP4 Base Media v1 [IS0 14496-12:2003]
  2. video/rio2016/finale/brasse/200.mp4 : ISO Media, MP4 v2 [ISO 14496-14]

  How can I convert 1 to 2 (mp41 to mp42) ?

  Thanks !