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• how to make sure the ffmpeg generate correct duration ?

  26 juin 2019, par Wang

  for example, the follow command create a 3 second video.

  ffmpeg -f lavfi -i color=c=red:r=30:d=3:size=800x600 red.nut

  But the ffprobe show duration is N/A :

  [STREAM]
  
  index=0
  
  codec_name=mpeg4
  
  codec_long_name=MPEG-4 part 2
  
  profile=Simple Profile
  
  codec_type=video
  
  codec_time_base=0/1
  
  codec_tag_string=FMP4
  
  codec_tag=0x34504d46
  
  width=800
  
  height=600
  
  coded_width=800
  
  coded_height=600
  
  has_b_frames=0
  
  sample_aspect_ratio=1:1
  
  display_aspect_ratio=4:3
  
  pix_fmt=yuv420p
  
  level=1
  
  color_range=unknown
  
  color_space=unknown
  
  color_transfer=unknown
  
  color_primaries=unknown
  
  chroma_location=left
  
  field_order=unknown
  
  timecode=N/A
  
  refs=1
  
  quarter_sample=false
  
  divx_packed=false
  
  id=N/A
  
  r_frame_rate=30/1
  
  avg_frame_rate=0/0
  
  time_base=1/61440
  
  start_pts=0
  
  start_time=0.000000
  
  duration_ts=N/A
  
  duration=N/A
  
  bit_rate=N/A
  
  max_bit_rate=N/A
  
  bits_per_raw_sample=N/A
  
  nb_frames=N/A
  
  nb_read_frames=N/A
  
  nb_read_packets=N/A
  
  DISPOSITION:default=0
  
  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
  
  DISPOSITION:timed_thumbnails=0
  
  TAG:encoder=Lavc57.107.100 mpeg4
  
  [/STREAM]

  Is there flag I can set to allow the ffmpeg generate correct duration_ts and duration ?

• How to encode H.264 video using FFmpeg C API and then open the output with a media player ?

  4 avril 2016, par GummiB

  I’m trying to encode a H.264 video with the FFMPEG C API.
  I have successfully compiled and executed the decoding/encoding example provided by FFMPEG.

  The problem I’m facing is that the .mpg file (encoded with AV_CODEC_ID_MPEG1VIDEO) the example creates works. Windows creates a thumbnail and everything. On the other hand the .h264 (encoded with AV_CODEC_ID_H264) file does not. When I try to play the file in VLC the play/pause button just flickers, no thumbnail in windows, no nothing.

  During encoding libx264 reports the following :

  [libx264 @ 004b81a0] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 AVX
  
  [libx264 @ 004b81a0] profile High, level 1.3
  
  [libx264 @ 004b81a0] frame I:3     Avg QP:26.79  size:  2116
  
  [libx264 @ 004b81a0] frame P:12    Avg QP:26.60  size:   789
  
  [libx264 @ 004b81a0] frame B:10    Avg QP:31.39  size:   499
  
  [libx264 @ 004b81a0] consecutive B-frames: 20.0% 80.0%
  
  [libx264 @ 004b81a0] mb I  I16..4: 78.3% 11.6% 10.1%
  
  [libx264 @ 004b81a0] mb P  I16..4: 77.4%  0.6%  0.1%  P16..4: 20.3%  0.7%  0.9%  0.0%  0.0%    skip: 0.0%
  
  [libx264 @ 004b81a0] mb B  I16..4:  0.0%  0.0%  0.0%  B16..8:  9.4%  0.2%  0.0%  direct:11.0%  skip:79.4%  L0:25.4% L1:35.4% BI:39.2%
  
  [libx264 @ 004b81a0] final ratefactor: 17.03
  
  [libx264 @ 004b81a0] 8x8 transform intra:3.4% inter:31.3%
  
  [libx264 @ 004b81a0] direct mvs  spatial:0.0% temporal:100.0%
  
  [libx264 @ 004b81a0] coded y,uvDC,uvAC intra: 4.4% 35.8% 1.6% inter: 1.3% 34.5% 9.5%
  
  [libx264 @ 004b81a0] i16 v,h,dc,p:  0%  0%  0% 100%
  
  [libx264 @ 004b81a0] i8 v,h,dc,ddl,ddr,vr,hd,vl,hu:  7% 20% 17% 49%  0%  0%  0%  1%  6%
  
  [libx264 @ 004b81a0] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 14%  7% 18% 45%  2%  7%  2%  3%  2%
  
  [libx264 @ 004b81a0] i8c dc,h,v,p:  2%  6%  4% 88%
  
  [libx264 @ 004b81a0] Weighted P-Frames: Y:0.0% UV:0.0%
  
  [libx264 @ 004b81a0] ref P L0: 95.6%  1.6%  2.2%  0.5%  0.2%
  
  [libx264 @ 004b81a0] ref B L0: 67.5% 28.5%  3.2%  0.8%
  
  [libx264 @ 004b81a0] kb/s:166.45

  "ffprobe.exe test.h264 -show_streams" returns

  [STREAM]
  
  index=0
  
  codec_name=h264
  
  codec_long_name=H.264 / AVC / MPEG-4 AVC / MPEG-4 part 10
  
  profile=High
  
  codec_type=video
  
  codec_time_base=1/50
  
  codec_tag_string=[0][0][0][0]
  
  codec_tag=0x0000
  
  width=352
  
  height=288
  
  has_b_frames=1
  
  sample_aspect_ratio=0:1
  
  display_aspect_ratio=0:1
  
  pix_fmt=yuv420p
  
  level=13
  
  timecode=N/A
  
  id=N/A
  
  r_frame_rate=50/2
  
  avg_frame_rate=25/1
  
  time_base=1/1200000
  
  start_pts=N/A
  
  start_time=N/A
  
  duration_ts=N/A
  
  duration=N/A
  
  bit_rate=N/A
  
  nb_frames=N/A
  
  nb_read_frames=N/A
  
  nb_read_packets=N/A
  
  DISPOSITION:default=0
  
  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
  
  [/STREAM]

  There you can see :

  start_time=N/A
  
  duration_ts=N/A
  
  duration=N/A

  I have tried countless changes to the AVCodecContext and multitude of parameters options to av_opt_set function. Still no luck getting a working H.264 video. I have even tried different builds of FFmpeg. No luck.

  I’m using the "FFmpeg git-0fb64da 32-bit Dev" build from Zeranoe and MinGw 4.7.2

• FFmpeg only reading one channel

  29 août 2017, par AbstractDissonance

  Trying to read a stereo wav file and ffmpeg is only reading one channel. ffprobe returns 2 channels.

  I have used -ac 2 and then added -channel_layout stereo but all return 1 channel(or basically filling half the buffer I created).

  Basically the output size of ffmpeg is about half the wav file size.

  What I would like is for it to return every channel in

  Channel1_sample1, channel2_sample1, ..., ChannelN_sample1, channel1_sample2, etc...

  But, in reality, I’d rather just have it work with stereo ;) I’m giving it plenty large enough buffer to read to, so that isn’t the problem either.

  Here is the output

  ffprobe.exe -hide_banner -v quiet -print_format flat -show_streams -i temp.wav
  
  streams.stream.0.index=0
  
  streams.stream.0.codec_name="pcm_s16le"
  
  streams.stream.0.codec_long_name="PCM signed 16-bit little-endian"
  
  streams.stream.0.profile="unknown"
  
  streams.stream.0.codec_type="audio"
  
  streams.stream.0.codec_time_base="1/44100"
  
  streams.stream.0.codec_tag_string="[1][0][0][0]"
  
  streams.stream.0.codec_tag="0x0001"
  
  streams.stream.0.sample_fmt="s16"
  
  streams.stream.0.sample_rate="44100"
  
  streams.stream.0.channels=2
  
  streams.stream.0.channel_layout="unknown"
  
  streams.stream.0.bits_per_sample=16
  
  streams.stream.0.id="N/A"
  
  streams.stream.0.r_frame_rate="0/0"
  
  streams.stream.0.avg_frame_rate="0/0"
  
  streams.stream.0.time_base="1/44100"
  
  streams.stream.0.start_pts="N/A"
  
  streams.stream.0.start_time="N/A"
  
  streams.stream.0.duration_ts=14200200
  
  streams.stream.0.duration="322.000000"
  
  streams.stream.0.bit_rate="1411200"
  
  streams.stream.0.max_bit_rate="N/A"
  
  streams.stream.0.bits_per_raw_sample="N/A"
  
  streams.stream.0.nb_frames="N/A"
  
  streams.stream.0.nb_read_frames="N/A"
  
  streams.stream.0.nb_read_packets="N/A"
  
  streams.stream.0.disposition.default=0
  
  streams.stream.0.disposition.dub=0
  
  streams.stream.0.disposition.original=0
  
  streams.stream.0.disposition.comment=0
  
  streams.stream.0.disposition.lyrics=0
  
  streams.stream.0.disposition.karaoke=0
  
  streams.stream.0.disposition.forced=0
  
  streams.stream.0.disposition.hearing_impaired=0
  
  streams.stream.0.disposition.visual_impaired=0
  
  streams.stream.0.disposition.clean_effects=0
  
  streams.stream.0.disposition.attached_pic=0
  
  streams.stream.0.disposition.timed_thumbnails=0
  
  ffmpeg.exe -i temp.wav -loglevel quiet -f s16le -ac 2 -channel_layout stereo -

  temp.wav is just a standard stereo wav file.