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• FFMPEG on Windows faststart command line with or without a +

  24 juillet 2014, par C0nw0nk

  So on the following wiki page i see ffmpeg tells us when using faststart for HTML5 compatibility we should use a + symbol.

  https://trac.ffmpeg.org/wiki/Encode/H.264#faststartforwebvideo

  -movflags +faststart

  But looking at command line examples on here and other sites everyone puts it in their command line like this.

  ffmpeg -i C:\vidtests\Wildlife.mp4 -movflags faststart C:\vidtests\Wildlife_fs.mp4

  So my question is should it matter if the + symbol is there or not ?

• Checkinstall equivalent on Red Hat (Santiago)

  29 octobre 2013, par Dalius

  I'm not familiar with Red Hat, never used it before.

  I'm installing ffmpeg from source, following this guide https://trac.ffmpeg.org/wiki/CentosCompilationGuide

  On Debian, after using make to compile ffmpeg, I would use checkinstall to install ffmpeg for all users. How can I do the same on Red Hat ?

• ffmpeg RTSP over TCP, RTP timestamps are always zero

  14 septembre 2021, par Azamat

  I'm trying to get timestamps from RTP packet. When I scan packets with Wireshark I get following output :
rtp_packet
I see that timestamps have incremented after several packets.
Issue that I have as following : when I read timestamp value from RTPDemuxContext->timestamp (rtp_demux_context->timestamp) in C, the value is always zero for several cameras, but for the majority of cameras the code works well.
Can you help to figure out is there are bug in cameras or bug in ffmpeg ?

  



  There is my code :

  



  double ntp_timestamp(AVFormatContext* pFormatCtx, uint32_t* last_rtcp_ts, double* base_time) {
RTSPState* rtsp_state = (RTSPState*) pFormatCtx->priv_data;
RTSPStream* rtsp_stream = rtsp_state->rtsp_streams[0];
RTPDemuxContext* rtp_demux_context = (RTPDemuxContext*) rtsp_stream->transport_priv;

uint32_t new_rtcp_ts = rtp_demux_context->last_rtcp_timestamp;

uint64_t last_ntp_time = 0;

if (new_rtcp_ts != *last_rtcp_ts) {
    *last_rtcp_ts = new_rtcp_ts;
    last_ntp_time = rtp_demux_context->last_rtcp_ntp_time;
    uint32_t seconds = ((last_ntp_time >> 32) & 0xffffffff) - 2208988800;
    uint32_t fraction  = (last_ntp_time & 0xffffffff);
    double useconds = ((double) fraction / 0xffffffff);
    *base_time = seconds + useconds;
}
uint32_t d_ts = rtp_demux_context->timestamp - *last_rtcp_ts;
return *base_time + d_ts / 90000.0;


  



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