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• libavcodec/jpeg2000 : fix precinct coordinate calculation

  11 avril 2020, par Gautam Ramakrishnan

  libavcodec/jpeg2000 : fix precinct coordinate calculation
  The calculation of precinct boundaries has been
  
  fixed. The precinct boundaries were calculated
  
  as an offset to the band boundary, but must
  
  instead be calculated as an offset from the
  
  reslevel. This patch fixes #4669 and #4679.
  Signed-off-by : Michael Niedermayer <michael@niedermayer.cc>
  

  • [DH] libavcodec/jpeg2000.c

• how to play nginx & rtmp based hls live stream on a remote machine

  21 mai 2020, par Ram

  I have installed nginx, rtmp and ffmpeg based hls live streaming working on ubuntu machine. I use this command to stream hls

  



  sudo ffmpeg -re -i sample.mp4 -vcodec libx264 -vprofile high -g 30 -acodec aac -strict -2 -f flv rtmp://localhost/show/stream2


  



  when I try to play this stream using VLC using following commands on the same machine it works well.

  



  http://myIp:8080/hls/stream2.m3u8


  



  or

  



  http://localhost:8080/hls/stream2.m3u8


  



  However when I try to access from remote computer connected to same WIFI, not able to play. VLC gives an error that unable to play the file.

  


• Using ffmpeg dll's from a windows 32 bit app

  8 avril 2020, par Derek

  I am trying to use ffmpeg via dll calls from a win32 app (compiled in clarion)

  



  I transcoded the example file encode_video.c and that worked 100% however I was left with a .h264 file instead of a .mp4 file.

  



  I then transcoded the example muxing.c however it crashes and I am at a loss for options.

  



  Any help would be most appreciated.

  



  Encode_mp4 ROUTINE
! avformat_alloc_output_context2 *******************************************************************************************
file_name = 'myvideo.mp4'
! Try guess format from filename
if CHECK_STACK then ds_SaveStack .
Result = avformat_alloc_output_context2(ThisPtrPtr, 0, NullCString, file_name);
if CHECK_STACK then ds_TestStack .
if Result < 0
    ds_OutputDebugString('avformat_alloc_output_context2 Try guess format failed, try mpeg', TRUE)
    CString1 = 'mpeg'
    if CHECK_STACK then ds_SaveStack .
    Result = avformat_alloc_output_context2(ThisPtrPtr, 0, CString1, file_name);
    if CHECK_STACK then ds_TestStack .
    if Result < 0
        ds_OutputDebugString('avformat_alloc_output_context2 failed', TRUE)
        stop('Could not allocate output format context')
        exit
    end
end
formater_ctxt &= (ThisPtrPtr)
!ds_OutputDebugString('formater_ctxt=' & address(formater_ctxt), TRUE)
assert(not(formater_ctxt &= NULL), 'Check AVFormatContext formater_ctxt')
do VerifyFormatContext
assert(formater_ctxt.oformat > 0, 'Check AVFormatContext formater_ctxt.oformat')
formater &= (formater_ctxt.oformat)
do VerifyFormat
ds_OutputDebugString('avformat_alloc_output_context2 OK', TRUE)

! avcodec_find_encoder *******************************************************************************************
if CHECK_STACK then ds_SaveStack .
encoder &= avcodec_find_encoder(formater.video_codec)
if CHECK_STACK then ds_TestStack .
if encoder &= NULL
    ds_OutputDebugString('avcodec_find_encoder failed', TRUE)
    stop('Could not find encoder')
    exit
end
do VerifyEncoder
ds_OutputDebugString('avcodec_find_encoder OK', TRUE)

! avformat_new_stream *******************************************************************************************
if CHECK_STACK then ds_SaveStack .
stream &= avformat_new_stream(formater_ctxt, encoder)
if CHECK_STACK then ds_TestStack .
if stream &= NULL 
    ds_OutputDebugString('avformat_new_stream failed', TRUE)
    stop('Could not create new stream')
    exit
end
do VerifyStream
stream.id = formater_ctxt.nb_streams-1
ds_OutputDebugString('avformat_new_stream OK', TRUE)

! avcodec_alloc_context3 *******************************************************************************************
if CHECK_STACK then ds_SaveStack .
encoder_ctxt &= avcodec_alloc_context3(encoder)
if CHECK_STACK then ds_TestStack .
if encoder_ctxt &= NULL 
    ds_OutputDebugString('avcodec_alloc_context3 failed', TRUE)
    stop('Could not allocate video codec context')
    exit
end
do VerifyEncoderContext
ds_OutputDebugString('avcodec_alloc_context3 OK', TRUE)

! Video settings *******************************************************************************************
do InitVideoSettings

assert(AV_CODEC_FLAG_GLOBAL_HEADER = bshift(1, 22), 'Check AV_CODEC_FLAG_GLOBAL_HEADER')
if band(formater.flags, AVFMT_GLOBALHEADER)
   encoder_ctxt.flags = bor(encoder_ctxt.flags, AV_CODEC_FLAG_GLOBAL_HEADER) !avctx->flags |= AV_CODEC_FLAG_GLOBAL_HEADER;
end

! avcodec_open2 *******************************************************************************************
if CHECK_STACK then ds_SaveStack .
Result = avcodec_open2(encoder_ctxt, encoder, 0)
if CHECK_STACK then ds_TestStack .
if Result < 0
    ds_OutputDebugString('avcodec_open2 failed.  Result=' & Result, TRUE)
    stop('Could not open codec')
    exit
end
ds_OutputDebugString('avcodec_open2 OK', TRUE)

! av_frame_alloc *******************************************************************************************
if CHECK_STACK then ds_SaveStack .
frame &= av_frame_alloc();
if CHECK_STACK then ds_TestStack .
if frame &= NULL
    ds_OutputDebugString('av_frame_alloc failed', TRUE)
    stop('Could not allocate video frame')
    exit
end
do VerifyFrame
frame.format = encoder_ctxt.pix_fmt
frame.width = encoder_ctxt.width
frame.height = encoder_ctxt.height
ds_OutputDebugString('av_frame_alloc OK', TRUE)

! av_frame_get_buffer *******************************************************************************************
if CHECK_STACK then ds_SaveStack .
Result = av_frame_get_buffer(frame, 32)
if CHECK_STACK then ds_TestStack .
if Result < 0
    ds_OutputDebugString('av_frame_get_buffer failed', TRUE)
    stop('Could not allocate video frame buffer Error = ' & Result)
    exit
end
do VerifyFrameBuffer
ds_OutputDebugString('av_frame_get_buffer OK', TRUE)

!frame->data offset=0  Array[8] of *int8_t
UseData0 &= (frame.data[1])
UseData1 &= (frame.data[2])
UseData2 &= (frame.data[3])

if CHECK_STACK then ds_SaveStack .
Result = avcodec_parameters_from_context(stream.codecpar, encoder_ctxt);
if CHECK_STACK then ds_TestStack .
if Result < 0
    ds_OutputDebugString('avcodec_parameters_from_context failed', TRUE)
    stop('Could not initialize stream parameters')
    exit
end
ds_OutputDebugString('avcodec_parameters_from_context OK', TRUE)

! av_dump_format *******************************************************************************************
ds_OutputDebugString('before call to av_dump_format  file_name=' & file_name, TRUE)
av_dump_format(formater_ctxt, 0, file_name, 1)


  



  I get a crash at last line - call to av_dump_format()

  



  If I comment this code then I get a crash on the very next lib call :

  



      ! avio_open *******************************************************************************************
if not(band(formater.flags, AVFMT_NOFILE)) 
    ds_OutputDebugString('before call to avio_open  file_name=' & file_name, TRUE)
    ThisInt &= address(formater_ctxt.pb)
    Result = avio_open(ThisInt, file_name, AVIO_FLAG_WRITE)


  



  Strangely if I comment the setup call to av_log_set_callback(my_log_callback) then the crash moves down to the next lib call : avformat_write_header