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• Why is this video file not supported in mobile safari ?

  30 septembre 2015, par pinkboi

  I’m using libffmpeg to generate my video and it’s playable on desktop browsers and many other places (including android). I looked at this earlier post, and the linked-to Apple guidelines but nothing stuck out at me as wrong about my stream. Are only certain framerates supported ? Here is the output of ffprobe -show_streams on a generated file :

  [STREAM]
  
  index=0
  
  codec_name=aac
  
  codec_long_name=AAC (Advanced Audio Coding)
  
  profile=LC
  
  codec_type=audio
  
  codec_time_base=1/44100
  
  codec_tag_string=mp4a
  
  codec_tag=0x6134706d
  
  sample_fmt=fltp
  
  sample_rate=44100
  
  channels=2
  
  channel_layout=stereo
  
  bits_per_sample=0
  
  id=N/A
  
  r_frame_rate=0/0
  
  avg_frame_rate=0/0
  
  time_base=1/44100
  
  start_pts=-2048
  
  start_time=-0.046440
  
  duration_ts=419840
  
  duration=9.520181
  
  bit_rate=63999
  
  max_bit_rate=N/A
  
  bits_per_raw_sample=N/A
  
  nb_frames=410
  
  nb_read_frames=N/A
  
  nb_read_packets=N/A
  
  DISPOSITION:default=1
  
  DISPOSITION:dub=0
  
  DISPOSITION:original=0
  
  DISPOSITION:comment=0
  
  DISPOSITION:lyrics=0
  
  DISPOSITION:karaoke=0
  
  DISPOSITION:forced=0
  
  DISPOSITION:hearing_impaired=0
  
  DISPOSITION:visual_impaired=0
  
  DISPOSITION:clean_effects=0
  
  DISPOSITION:attached_pic=0
  
  TAG:language=und
  
  TAG:handler_name=SoundHandler
  
  [/STREAM]
  
  [STREAM]
  
  index=1
  
  codec_name=h264
  
  codec_long_name=H.264 / AVC / MPEG-4 AVC / MPEG-4 part 10
  
  profile=Constrained Baseline
  
  codec_type=video
  
  codec_time_base=1/48
  
  codec_tag_string=avc1
  
  codec_tag=0x31637661
  
  width=500
  
  height=500
  
  has_b_frames=0
  
  sample_aspect_ratio=0:1
  
  display_aspect_ratio=0:1
  
  pix_fmt=yuv420p
  
  level=30
  
  color_range=N/A
  
  color_space=unknown
  
  color_transfer=unknown
  
  color_primaries=unknown
  
  chroma_location=left
  
  timecode=N/A
  
  is_avc=1
  
  nal_length_size=4
  
  id=N/A
  
  r_frame_rate=24/1
  
  avg_frame_rate=24/1
  
  time_base=1/12288
  
  start_pts=0
  
  start_time=0.000000
  
  duration_ts=92672
  
  duration=7.541667
  
  bit_rate=24286
  
  max_bit_rate=N/A
  
  bits_per_raw_sample=8
  
  nb_frames=181
  
  nb_read_frames=N/A
  
  nb_read_packets=N/A
  
  DISPOSITION:default=1
  
  DISPOSITION:dub=0
  
  DISPOSITION:original=0
  
  DISPOSITION:comment=0
  
  DISPOSITION:lyrics=0
  
  DISPOSITION:karaoke=0
  
  DISPOSITION:forced=0
  
  DISPOSITION:hearing_impaired=0
  
  DISPOSITION:visual_impaired=0
  
  DISPOSITION:clean_effects=0
  
  DISPOSITION:attached_pic=0
  
  TAG:language=und
  
  TAG:handler_name=VideoHandler
  
  [/STREAM]

• which function in libavcodec should i call to compress video ?

  27 novembre 2019, par milad

  I have an open source program which is in C language and use libavcodec.

  This program produce a video.m4v video that it’s size is 65 Mbyte and it’s duration is 4 minutes and 36 seconds.

  When I run below command it’s size reduce to 4.2 Mbyte.

  ffmpeg -i video.m4v video_new.m4v

  My Questions are :

  1.Why ffmpeg produce same video with less size while codec and extension doesn’t change ?

  2. How can I compress my video to this size in first program ? Should I call a specific function ?

• Does ffmpeg rtp_mpegts muxer support setting DVB triplet ?

  19 février 2021, par drake7

  It seems ffmpeg lets you set the DVB triplet with UDP but not with RTP.

  


  FYI : This is a followup on my findings about the rtp_mpegts muxer compared to the mpegts muxer : Question

  


  In my tests I was using ffmpeg version 4.3.1-2021-01-01-full_build-www.gyan.dev on windows.

  


  findings

  


  I analyzed my streams with dectec's "StreamXpert" :

  


  


  • With UDP and it's mpegts muxer, the DVB triplet can be set (1)

    


  


  • With RTP and it's rtp_mpegts muxer, the DVB triplet is ignored (3) (Note that 3a and 3b create very similar results in "StreamXpert".)

    


  


  • Using UDP with DVB triplet as input and output with RTP ignores the DVB triplet (2)

    


  



  


  Interestingly, leaving out the following options...

  


  -pcr_period 20 -pat_period 0.10 -sdt_period 0.25 -metadata:s:a:0 language=nya \
-mpegts_flags +pat_pmt_at_frames -mpegts_flags system_b


  


  ... the rtp_mpegts muxer (3b) creates a valid DVB transport stream, while the the mpegts muxer (4) does not.

  


  ffmpeg params :

  


  



  


  muxer : mpegts (udp)

  


  ffmpeg -f lavfi -i testsrc -r 25 -c:v libx264 -pix_fmt yuv420p -profile:v main -level 3.1 -preset veryfast -vf scale=1280:720,setdar=dar=16/9 -an -bsf:v h264_mp4toannexb -b:v 4M -muxrate 8M \
-pcr_period 20 -pat_period 0.10 -sdt_period 0.25 -metadata:s:a:0 language=nya -mpegts_flags +pat_pmt_at_frames \
-mpegts_transport_stream_id 0x005A \
-mpegts_original_network_id 0x005B \
-mpegts_service_id 0x005C \
-mpegts_pmt_start_pid 0x005D -mpegts_start_pid 0x005E -mpegts_service_type advanced_codec_digital_hdtv \
-metadata service_provider="Provider foo" \
-metadata service_name="Service bar" \
-mpegts_flags system_b -flush_packets 0 \
-f mpegts "udp://239.10.33.10:1234?pkt_size=1316"


  


  



  


  muxer : rtp_mpegts (rtp)

  


  ffmpeg -i "udp://239.10.33.10:1234" -map 0 -c copy \
-f rtp_mpegts "rtp://239.10.33.11:1234?pkt_size=1316"


  


  



  


  a) muxer : rtp_mpegts (rtp)

  


  ffmpeg -f lavfi -i testsrc -r 25 -c:v libx264 -pix_fmt yuv420p -profile:v main -level 3.1 -preset veryfast -vf scale=1280:720,setdar=dar=16/9 -an -bsf:v h264_mp4toannexb -b:v 4M -muxrate 8M \
-pcr_period 20 -pat_period 0.10 -sdt_period 0.25 -metadata:s:a:0 language=nya -mpegts_flags +pat_pmt_at_frames \
-mpegts_transport_stream_id 0x005A \
-mpegts_original_network_id 0x005B \
-mpegts_service_id 0x005C \
-mpegts_pmt_start_pid 0x005D -mpegts_start_pid 0x005E -mpegts_service_type advanced_codec_digital_hdtv \
-metadata service_provider="Provider foo" \
-metadata service_name="Service bar" \
-mpegts_flags system_b -flush_packets 0 \
-f rtp_mpegts "rtp://239.10.33.10:1234?pkt_size=1316"


  


  b) muxer : rtp_mpegts (rtp) (omitting some options)

  


  ffmpeg -f lavfi -i testsrc -r 25 -c:v libx264 -vf scale=1280:720,setdar=dar=16/9 -b:v 4M -muxrate 8M \
-mpegts_transport_stream_id 0x005A \
-mpegts_original_network_id 0x005B \
-mpegts_service_id 0x005C -mpegts_pmt_start_pid 0x005D -mpegts_start_pid 0x005E \
-mpegts_service_type advanced_codec_digital_hdtv \
-metadata service_provider="Provider foo" \
-metadata service_name="Service bar" \
-f rtp_mpegts "rtp://239.10.33.10:1234"


  


  



  


  muxer : mpegts (udp) (omitting some options)

  


  ffmpeg -f lavfi -i testsrc -r 25 -c:v libx264 -vf scale=1280:720,setdar=dar=16/9 -b:v 4M -muxrate 8M \
-mpegts_transport_stream_id 0x005A \
-mpegts_original_network_id 0x005B \
-mpegts_service_id 0x005C -mpegts_pmt_start_pid 0x005D -mpegts_start_pid 0x005E \
-mpegts_service_type advanced_codec_digital_hdtv \
-metadata service_provider="Provider foo" \
-metadata service_name="Service bar" \
-f mpegts "udp://239.10.33.10:1234"


  


  Analyzing the transport stream