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• avcodec/xbmdec : get_nibble() minor speed increase, and binary reduction

  1er février 2021, par Jose Da Silva

  avcodec/xbmdec : get_nibble() minor speed increase, and binary reduction
  Replace av_isxdigit(*ptr) and convert(*ptr) with get_nibble(*ptr) which
  
  returns a valid nibble==0x00..0x0f or false==255 for all other values.
  
  This way we only need to work with *ptr once instead of twice.
  Removing inline av_isxdigit(x) functions also shrinks executable size.
  Signed-off-by : Joe Da Silva <digital@joescat.com>
  

  • [DH] libavcodec/xbmdec.c

• FFMPEG convert RTSP to RTMP overlay pipeline

  5 juillet 2021, par Helpme-villain

  I have ffmpeg command that I want to convert RTSP to RTMP broadcast.
Before the broadcast, I want to overlay the frame with an image.

  


  So, here is my pipeline :

  


  

  1. read stream from RTSP

  


  2. overlay an image

  


  3. broadcast RTMP (Youtube)

  


  


  I tried some command, but I met the error message :

  


  

  • Here is my command

  


  


  The reason why I used anullsrc is because the RTMP server must input an audio stream, but my video stream has no audio

  


  ffmpeg -i image.jpg -i /server> -filter_complex "[1:v][0:v]overlay"  -f lavfi -i anullsrc -rtsp_transport udp -t 12:00:00 -pix_fmt + -tune zerolatency -sstrict expreimental -f flv / server>


  


  

  • Error Message

  


  


  [rtsp @ 0000021890521700] Thread message queue blocking; consider raising the thread_queue_size option (current value: 8)
The filters 'graph 0 input from stream 0:0' and 'Parsed_overlay_0' do not have a common format and automatic conversion is disabled.
Error reinitializing filters!
Failed to inject frame into filter network: Invalid argument
Error while processing the decoded data for stream #0:0
Conversion failed!


  


  

  • all the message

  


  


  Input #0, image2, from 'image.jpg':
  Duration: 00:00:00.04, start: 0.000000, bitrate: 1763 kb/s
  Stream #0:0: Video: mjpeg (Baseline), yuvj420p(pc, bt470bg/unknown/unknown), 225x225 [SAR 1:1 DAR 1:1], 25 fps, 25 tbr, 25 tbn
Input #1, rtsp, from 'rtsp://~~~~~~~~~~~~~~~':
  Metadata:
    title           : RTMP Server 
    comment         : RTMP Server Session Description : standard
  Duration: N/A, start: 0.034000, bitrate: N/A
  Stream #1:0: Video: h264 (Main), yuvj420p(pc, bt709, progressive), 1920x1080, 30 tbr, 90k tbn
Input #2, lavfi, from 'anullsrc':
  Duration: N/A, start: 0.000000, bitrate: 705 kb/s
  Stream #2:0: Audio: pcm_u8, 44100 Hz, stereo, u8, 705 kb/s
Codec AVOption tune (The metric that the encoder tunes for. Automatically chosen by the encoder by default) specified for output file #0 (rtmp://a.rtmp.youtube.com/live2/~~~~~~~~~~~~~~~) has not been used for any stream. The most likely reason is either wrong type (e.g. a video option with no video streams) or that it is a private option of some encoder which was not actually used for any stream.
Stream mapping:
  Stream #0:0 (mjpeg) -> overlay:overlay (graph 0)
  Stream #1:0 (h264) -> overlay:main (graph 0)
  overlay (graph 0) -> Stream #0:0 (flv)
  Stream #2:0 -> #0:1 (pcm_u8 (native) -> mp3 (libmp3lame))
Press [q] to stop, [?] for help
[rtsp @ 0000021890521700] Thread message queue blocking; consider raising the thread_queue_size option (current value: 8)
The filters 'graph 0 input from stream 0:0' and 'Parsed_overlay_0' do not have a common format and automatic conversion is disabled.
Error reinitializing filters!
Failed to inject frame into filter network: Invalid argument
Error while processing the decoded data for stream #0:0
Conversion failed!


  


  Thanks.

  


• FFMPEG Conversion improve quality

  1er octobre 2019, par user726720

  I have some questions regarding ffmpeg :

  I need to convert the XDCAM HD422 (yuv422p) to AVC (h.264, mp4). I’m doing it as follows :

  ffmpeg.exe -y -i path\abc.mxf  -ab 128k -acodec aac -ac 2 -strict -2 -b:v 12000k -f mp4 -g 34 -pix_fmt yuv420p -r 25 -s 1920x1080 -vcodec h264 -preset ultrafast h264file.mp4

  I have check the mp4 on a broadcast monitor and there are some visible color saturation issue’s. The quality doesn’t match the original XDCAM HD422

  1. What changes do I need to make in the above parameters to fix this ?
  2. My original file is a yuv422p and I’m using yuv420p in the above ffmpeg command, does this make a difference in the quality.
  3. Should change the preset from ultrafast to Fast make a difference.
  4. Will using the libx264 make any difference ?
  5. How does ffmeg encode from one format to another. Does it simply do a direct conversion or does it extract the RAW (yuv) from the XDCAM and then encode it into MP4 ?

  I’m just brainstorming how to improve the quality so it matches the that of XDCAM, any suggestions would be highly appreciated.