Recherche avancée

Sur d’autres sites (9053)

• I have an application in flask where it streams a camera using ffmpeg, the problem is that I can not display the video from the camera using the GPU [closed]

  17 janvier, par Ruben

  I'll put you in context, I am using flask (python) to display a camera in the browser to stream it, for this I use the following Python code :

  


  command = [
     'ffmpeg',
     '-loglevel', 'warning',
     '-rtsp_transport', 'tcp',
     '-i', self.config['url'],
     '-map', '0:v:0', # fuerzo que solo procese el video
     '-vf', f'fps={self.config["fps"]},scale=640:360:force_original_aspect_ratio=decrease',
     '-c:v', 'h264_nvenc', # especificamos que queremos tirar de la gpu de nvidia
     '-preset', 'p7', # ajusta para la maxima calidad/velocidad (p1 mas rapida pero peor calidad - p7 más lento pero mejor calidad)
     '-qp', self.config['quality'], # control de calidad del codificador (0 [mejor calidad] - 51 [peor calidad])
     '-pix_fmt', 'yuv444p', # se mete explicitamente el formato de pixeles
     '-color_range', 'pc',
     '-an', # desactiva el audio
     '-f', 'image2pipe',
     'pipe:1'
] 

self.process = subprocess.Popen(
   command,
   stdout=subprocess.PIPE,
   stderr=subprocess.PIPE,
   bufsize=10**8
)


  


  The problem is that it does not display the video streaming, but it connects correctly to the camera.

  


  On the other hand, It show me the following warnings, which may have something to do with the display, it's probably the second warning that has to do with the pixel format :

  


  DEBUG :main:FFmpeg [camera1] : Guessed Channel Layout for Input Stream #0.1 : mono
DEBUG :main:FFmpeg [camera1] : [swscaler @ 0x560f70b78680] deprecated pixel format used, make sure you did set range correctly

  


  The server has different encodes installed :

  


  DEV.LS h264 H.264 / AVC / MPEG-4 AVC / MPEG-4 part 10 (decoders : h264 h264_v4l2m2m h264_qsv h264_cuvid ) (encoders : libx264 libx264rgb h264_nvenc h264_omx h264_qsv h264_v4l2m2m h264_vaapi nvenc nvenc_h264 )

  


  Y uso el h264_nvenc, tambien el servidor tiene soporte de aceleración de hardware con :

  


  libavutil 56. 70.100 / 56. 70.100
libavcodec 58.134.100 / 58.134.100
libavformat 58. 76.100 / 58. 76.100
libavdevice 58. 13.100 / 58. 13.100
libavfilter 7.110.100 / 7.110.100
libswscale 5. 9.100 / 5. 9.100
libswresample 3. 9.100 / 3. 9.100
libpostproc 55. 9.100 / 55. 9.100
Hardware acceleration methods :
vdpau
cuda
vaapi
qsv
drm
opencl

  


  Between them h264_nvenc uses cuda

  


  I expand a little on the information it provides me when using h264_nvenc :

  


  Encoder h264_nvenc [NVIDIA NVENC H.264 encoder]:&#xA;    General capabilities: dr1 delay hardware&#xA;    Threading capabilities: none&#xA;    Supported hardware devices: cuda cuda&#xA;    Supported pixel formats: yuv420p nv12 p010le yuv444p p016le yuv444p16le bgr0 rgb0 cuda&#xA;h264_nvenc AVOptions:&#xA;  -preset            <int>        E..V....... Set the encoding preset (from 0 to 18) (default p4)&#xA;     default         0            E..V.......&#xA;     slow            1            E..V....... hq 2 passes&#xA;     medium          2            E..V....... hq 1 pass&#xA;     fast            3            E..V....... hp 1 pass&#xA;     hp              4            E..V.......&#xA;     hq              5            E..V.......&#xA;     bd              6            E..V.......&#xA;     ll              7            E..V....... low latency&#xA;     llhq            8            E..V....... low latency hq&#xA;     llhp            9            E..V....... low latency hp&#xA;     lossless        10           E..V.......&#xA;     losslesshp      11           E..V.......&#xA;     p1              12           E..V....... fastest (lowest quality)&#xA;     p2              13           E..V....... faster (lower quality)&#xA;     p3              14           E..V....... fast (low quality)&#xA;     p4              15           E..V....... medium (default)&#xA;     p5              16           E..V....... slow (good quality)&#xA;     p6              17           E..V....... slower (better quality)&#xA;     p7              18           E..V....... slowest (best quality)&#xA;  -tune              <int>        E..V....... Set the encoding tuning info (from 1 to 4) (default hq)&#xA;     hq              1            E..V....... High quality&#xA;     ll              2            E..V....... Low latency&#xA;     ull             3            E..V....... Ultra low latency&#xA;     lossless        4            E..V....... Lossless&#xA;  -profile           <int>        E..V....... Set the encoding profile (from 0 to 3) (default main)&#xA;     baseline        0            E..V.......&#xA;     main            1            E..V.......&#xA;     high            2            E..V.......&#xA;     high444p        3            E..V.......&#xA;  -level             <int>        E..V....... Set the encoding level restriction (from 0 to 62) (default auto)&#xA;     auto            0            E..V.......&#xA;     1               10           E..V.......&#xA;     1.0             10           E..V.......&#xA;     1b              9            E..V.......&#xA;     1.0b            9            E..V.......&#xA;     1.1             11           E..V.......&#xA;     1.2             12           E..V.......&#xA;     1.3             13           E..V.......&#xA;     2               20           E..V.......&#xA;     2.0             20           E..V.......&#xA;     2.1             21           E..V.......&#xA;     2.2             22           E..V.......&#xA;     3               30           E..V.......&#xA;     3.0             30           E..V.......&#xA;     3.1             31           E..V.......&#xA;     3.2             32           E..V.......&#xA;     4               40           E..V.......&#xA;     4.0             40           E..V.......&#xA;     4.1             41           E..V.......&#xA;     4.2             42           E..V.......&#xA;     5               50           E..V.......&#xA;     5.0             50           E..V.......&#xA;     5.1             51           E..V.......&#xA;     5.2             52           E..V.......&#xA;     6.0             60           E..V.......&#xA;     6.1             61           E..V.......&#xA;     6.2             62           E..V.......&#xA;  -rc                <int>        E..V....... Override the preset rate-control (from -1 to INT_MAX) (default -1)&#xA;     constqp         0            E..V....... Constant QP mode&#xA;     vbr             1            E..V....... Variable bitrate mode&#xA;     cbr             2            E..V....... Constant bitrate mode&#xA;     vbr_minqp       8388612      E..V....... Variable bitrate mode with MinQP (deprecated)&#xA;     ll_2pass_quality 8388616      E..V....... Multi-pass optimized for image quality (deprecated)&#xA;     ll_2pass_size   8388624      E..V....... Multi-pass optimized for constant frame size (deprecated)&#xA;     vbr_2pass       8388640      E..V....... Multi-pass variable bitrate mode (deprecated)&#xA;     cbr_ld_hq       8388616      E..V....... Constant bitrate low delay high quality mode&#xA;     cbr_hq          8388624      E..V....... Constant bitrate high quality mode&#xA;     vbr_hq          8388640      E..V....... Variable bitrate high quality mode&#xA;  -rc-lookahead      <int>        E..V....... Number of frames to look ahead for rate-control (from 0 to INT_MAX) (default 0)&#xA;  -surfaces          <int>        E..V....... Number of concurrent surfaces (from 0 to 64) (default 0)&#xA;  -cbr               <boolean>    E..V....... Use cbr encoding mode (default false)&#xA;  -2pass             <boolean>    E..V....... Use 2pass encoding mode (default auto)&#xA;  -gpu               <int>        E..V....... Selects which NVENC capable GPU to use. First GPU is 0, second is 1, and so on. (from -2 to INT_MAX) (default any)&#xA;     any             -1           E..V....... Pick the first device available&#xA;     list            -2           E..V....... List the available devices&#xA;  -delay             <int>        E..V....... Delay frame output by the given amount of frames (from 0 to INT_MAX) (default INT_MAX)&#xA;  -no-scenecut       <boolean>    E..V....... When lookahead is enabled, set this to 1 to disable adaptive I-frame insertion at scene cuts (default false)&#xA;  -forced-idr        <boolean>    E..V....... If forcing keyframes, force them as IDR frames. (default false)&#xA;  -b_adapt           <boolean>    E..V....... When lookahead is enabled, set this to 0 to disable adaptive B-frame decision (default true)&#xA;  -spatial-aq        <boolean>    E..V....... set to 1 to enable Spatial AQ (default false)&#xA;  -spatial_aq        <boolean>    E..V....... set to 1 to enable Spatial AQ (default false)&#xA;  -temporal-aq       <boolean>    E..V....... set to 1 to enable Temporal AQ (default false)&#xA;  -temporal_aq       <boolean>    E..V....... set to 1 to enable Temporal AQ (default false)&#xA;  -zerolatency       <boolean>    E..V....... Set 1 to indicate zero latency operation (no reordering delay) (default false)&#xA;  -nonref_p          <boolean>    E..V....... Set this to 1 to enable automatic insertion of non-reference P-frames (default false)&#xA;  -strict_gop        <boolean>    E..V....... Set 1 to minimize GOP-to-GOP rate fluctuations (default false)&#xA;  -aq-strength       <int>        E..V....... When Spatial AQ is enabled, this field is used to specify AQ strength. AQ strength scale is from 1 (low) - 15 (aggressive) (from 1 to 15) (default 8)&#xA;  -cq                <float>      E..V....... Set target quality level (0 to 51, 0 means automatic) for constant quality mode in VBR rate control (from 0 to 51) (default 0)&#xA;  -aud               <boolean>    E..V....... Use access unit delimiters (default false)&#xA;  -bluray-compat     <boolean>    E..V....... Bluray compatibility workarounds (default false)&#xA;  -init_qpP          <int>        E..V....... Initial QP value for P frame (from -1 to 51) (default -1)&#xA;  -init_qpB          <int>        E..V....... Initial QP value for B frame (from -1 to 51) (default -1)&#xA;  -init_qpI          <int>        E..V....... Initial QP value for I frame (from -1 to 51) (default -1)&#xA;  -qp                <int>        E..V....... Constant quantization parameter rate control method (from -1 to 51) (default -1)&#xA;  -weighted_pred     <int>        E..V....... Set 1 to enable weighted prediction (from 0 to 1) (default 0)&#xA;  -coder             <int>        E..V....... Coder type (from -1 to 2) (default default)&#xA;     default         -1           E..V.......&#xA;     auto            0            E..V.......&#xA;     cabac           1            E..V.......&#xA;     cavlc           2            E..V.......&#xA;     ac              1            E..V.......&#xA;     vlc             2            E..V.......&#xA;  -b_ref_mode        <int>        E..V....... Use B frames as references (from 0 to 2) (default disabled)&#xA;     disabled        0            E..V....... B frames will not be used for reference&#xA;     each            1            E..V....... Each B frame will be used for reference&#xA;     middle          2            E..V....... Only (number of B frames)/2 will be used for reference&#xA;  -a53cc             <boolean>    E..V....... Use A53 Closed Captions (if available) (default true)&#xA;  -dpb_size          <int>        E..V....... Specifies the DPB size used for encoding (0 means automatic) (from 0 to INT_MAX) (default 0)&#xA;  -multipass         <int>        E..V....... Set the multipass encoding (from 0 to 2) (default disabled)&#xA;     disabled        0            E..V....... Single Pass&#xA;     qres            1            E..V....... Two Pass encoding is enabled where first Pass is quarter resolution&#xA;     fullres         2            E..V....... Two Pass encoding is enabled where first Pass is full resolution&#xA;  -ldkfs             <int>        E..V....... Low delay key frame scale; Specifies the Scene Change frame size increase allowed in case of single frame VBV and CBR (from 0 to 255) (default 0)&#xA;</int></int></int></boolean></int></int></int></int></int></int></int></boolean></boolean></float></int></boolean></boolean></boolean></boolean></boolean></boolean></boolean></boolean></boolean></boolean></int></int></boolean></boolean></int></int></int></int></int></int></int>

  


  If anyone has some idea or needs more information to help me, I would appreciate it.

  


• Invalid data stream in media could not be discarded by FFMPEG. Why is it staying and how to discard it ?

  5 décembre 2020, par Link-akro

  I have downloaded a [short media][1] i intend to convert then i will use the result as basis to practice and test any and all FFMPEG commands i learn or use later.

  


  That video seems to have an unknown invalid stream which never disappears no matter everything i tried to discard it. When i try to work with it later i get various problems like missing codec or no stream which is not the focus here but the reason why i got stubborn to remove the things i cannot deal with.

  


  The following probing prints a warning in yellow color on last row.

  


   > ffprobe -hide_banner -show_streams Movie_Countdown-youtube_I1vMKZ1kvg0.mov

Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'Movie_Countdown-youtube_I1vMKZ1kvg0.mov':
  Metadata:
    major_brand     : qt
    minor_version   : 537199360
    compatible_brands: qt
    creation_time   : 2015-05-20T13:45:55.000000Z
  Duration: 00:00:10.00, start: 0.000000, bitrate: 11474 kb/s
    Stream #0:0(eng): Video: h264 (Main) (avc1 / 0x31637661), yuv420p(tv, bt709), 1920x1080, 9930 kb/s, SAR 1:1 DAR 16:9, 25 fps, 25 tbr, 25 tbn, 50 tbc (default)
    Metadata:
      creation_time   : 2015-05-20T13:45:55.000000Z
      handler_name    : Apple Video Media Handler
      encoder         : H.264
      timecode        : 00:00:00:00
    Stream #0:1(eng): Audio: pcm_s16le (sowt / 0x74776F73), 48000 Hz, stereo, s16, 1536 kb/s (default)
    Metadata:
      creation_time   : 2015-05-20T13:45:56.000000Z
      handler_name    : Apple Sound Media Handler
      timecode        : 00:00:00:00
    Stream #0:2(eng): Data: none (tmcd / 0x64636D74), 0 kb/s (default)
    Metadata:
      creation_time   : 2015-05-20T13:46:11.000000Z
      handler_name    : Time Code Media Handler
      timecode        : 00:00:00:00
Unsupported codec with id 0 for input stream 2


  


  Below the streams output. I split the text so you see the warning without searching in the middle.

  


  [STREAM]
index=0
codec_name=h264
codec_long_name=H.264 / AVC / MPEG-4 AVC / MPEG-4 part 10
profile=Main
codec_type=video
codec_time_base=1/50
codec_tag_string=avc1
codec_tag=0x31637661
width=1920
height=1080
coded_width=1920
coded_height=1088
closed_captions=0
has_b_frames=0
sample_aspect_ratio=1:1
display_aspect_ratio=16:9
pix_fmt=yuv420p
level=40
color_range=tv
color_space=bt709
color_transfer=bt709
color_primaries=bt709
chroma_location=left
field_order=unknown
timecode=N/A
refs=1
is_avc=true
nal_length_size=4
id=N/A
r_frame_rate=25/1
avg_frame_rate=25/1
time_base=1/25
start_pts=0
start_time=0.000000
duration_ts=250
duration=10.000000
bit_rate=9930739
max_bit_rate=N/A
bits_per_raw_sample=8
nb_frames=250
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
DISPOSITION:timed_thumbnails=0
TAG:creation_time=2015-05-20T13:45:55.000000Z
TAG:language=eng
TAG:handler_name=Apple Video Media Handler
TAG:encoder=H.264
TAG:timecode=00:00:00:00
[/STREAM]
[STREAM]
index=1
codec_name=pcm_s16le
codec_long_name=PCM signed 16-bit little-endian
profile=unknown
codec_type=audio
codec_time_base=1/48000
codec_tag_string=sowt
codec_tag=0x74776f73
sample_fmt=s16
sample_rate=48000
channels=2
channel_layout=stereo
bits_per_sample=16
id=N/A
r_frame_rate=0/0
avg_frame_rate=0/0
time_base=1/48000
start_pts=0
start_time=0.000000
duration_ts=480000
duration=10.000000
bit_rate=1536000
max_bit_rate=N/A
bits_per_raw_sample=N/A
nb_frames=480000
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
DISPOSITION:timed_thumbnails=0
TAG:creation_time=2015-05-20T13:45:56.000000Z
TAG:language=eng
TAG:handler_name=Apple Sound Media Handler
TAG:timecode=00:00:00:00
[/STREAM]
[STREAM]
index=2
codec_name=unknown
codec_long_name=unknown
profile=unknown
codec_type=data
codec_tag_string=tmcd
codec_tag=0x64636d74
id=N/A
r_frame_rate=0/0
avg_frame_rate=25/1
time_base=1/25
start_pts=0
start_time=0.000000
duration_ts=250
duration=10.000000
bit_rate=3
max_bit_rate=N/A
bits_per_raw_sample=N/A
nb_frames=1
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
DISPOSITION:timed_thumbnails=0
TAG:creation_time=2015-05-20T13:46:11.000000Z
TAG:language=eng
TAG:handler_name=Time Code Media Handler
TAG:timecode=00:00:00:00
[/STREAM]


  


  I scaled it down and recoded it for starters and i tried to discard the data stream with -dn and failed other methods i will mention at the end.
The output so far suggests that discarding should have worked since alternative datas are 0kB and no stream 2 is listed.

  


   > ffmpeg -hide_banner -dn -i C:\Users\admin-dix\Downloads\Movie_Countdown-youtube_I1vMKZ1kvg0.mov -vf "scale=h=450:w=800" -f mp4 -c:a aac -c:v libx264 mov_countdown.mp4

Output #0, mp4, to 'mov_countdown.mp4':
  Metadata:
    major_brand     : qt
    minor_version   : 537199360
    compatible_brands: qt
    encoder         : Lavf58.45.100
    Stream #0:0(eng): Video: h264 (libx264) (avc1 / 0x31637661), yuv420p(progressive), 800x450 [SAR 1:1 DAR 16:9], q=-1--1, 0.04 fps, 12800 tbn, 25 tbc (default)
    Metadata:
      creation_time   : 2015-05-20T13:45:55.000000Z
      handler_name    : Apple Video Media Handler
      timecode        : 00:00:00:00
      encoder         : Lavc58.91.100 libx264
    Side data:
      cpb: bitrate max/min/avg: 0/0/0 buffer size: 0 vbv_delay: N/A
    Stream #0:1(eng): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 128 kb/s (default)
    Metadata:
      creation_time   : 2015-05-20T13:45:56.000000Z
      handler_name    : Apple Sound Media Handler
      timecode        : 00:00:00:00
      encoder         : Lavc58.91.100 aac
frame=  250 fps= 43 q=-1.0 Lsize=     342kB time=00:00:10.00 bitrate= 280.1kbits/s speed= 1.7x
video:175kB audio:159kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 2.710857%


  


  Then ffprobe disagrees, there is still the stream and the warning.

  


  ffprobe mov_countdown.mp4

Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'mov_countdown.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    encoder         : Lavf58.45.100
  Duration: 00:00:10.02, start: 0.000000, bitrate: 279 kb/s
    Stream #0:0(eng): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 800x450 [SAR 1:1 DAR 16:9], 142 kb/s, 25 fps, 25 tbr, 12800 tbn, 50 tbc (default)
    Metadata:
      handler_name    : Apple Video Media Handler
      timecode        : 00:00:00:00
    Stream #0:1(eng): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 129 kb/s (default)
    Metadata:
      handler_name    : Apple Sound Media Handler
    Stream #0:2(eng): Data: none (tmcd / 0x64636D74), 0 kb/s
    Metadata:
      handler_name    : Apple Video Media Handler
      timecode        : 00:00:00:00
Unsupported codec with id 0 for input stream 2


  


  I tried negative mapping as per this answer -map 0:d which failed. I did not understand -discard option as ffmpeg documentation refers to from the -vn,-an,-dn entries as it does not specify a stream.

  


  Why does it do that and how can i remove that stream i do not know and do not want to care about in future tests ?

  


  [1] : Clean Retro Movie Countdown - YouTube from Philippe Moesch https://www.youtube.com/watch?v=I1vMKZ1kvg0

  


• FFmpeg remove silence with exact duration detected by detect silence

  17 mars 2021, par dav

  I have an audio file, that have some silences, which I am detecting with ffmpeg detectsilence and then trying to remove with removesilence, however there is some strange behavior. Specifically :

  


  1) File's Basic info based on ffprobe show_streams

  


  Input #0, mp3, from 'my_file.mp3':
  Metadata:
    encoder         : Lavf58.64.100
  Duration: 00:00:25.22, start: 0.046042, bitrate: 32 kb/s
    Stream #0:0: Audio: mp3, 24000 Hz, mono, fltp, 32 kb/s


  


  2) Using detectsilence

  


  ffmpeg -i my_file.mp3 -af silencedetect=noise=-50dB:d=0.2 -f null -


  


  I get this result

  


  [mp3float @ 000001ee50074280] overread, skip -7 enddists: -1 -1
[silencedetect @ 000001ee5008a1c0] silence_start: 6.21417
[silencedetect @ 000001ee5008a1c0] silence_end: 6.91712 | silence_duration: 0.702958
[silencedetect @ 000001ee5008a1c0] silence_start: 16.44
[silencedetect @ 000001ee5008a1c0] silence_end: 17.1547 | silence_duration: 0.714708
[mp3float @ 000001ee50074280] overread, skip -10 enddists: -3 -3
[mp3float @ 000001ee50074280] overread, skip -5 enddists: -4 -4
[silencedetect @ 000001ee5008a1c0] silence_start: 24.4501
size=N/A time=00:00:25.17 bitrate=N/A speed=1.32e+03x
video:0kB audio:1180kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: unknown
[silencedetect @ 000001ee5008a1c0] silence_end: 25.176 | silence_duration: 0.725917


  


  That also match the values and points based on Adobe Audition

  


  

  


  So far all good.

  


  3) Now, based on some calculations (which is based on application's logic on what should be the final duration of the audio) I am trying to delete the silence with "0.725917"s duration. For that, based on ffmpeg docs (https://ffmpeg.org/ffmpeg-filters.html#silencedetect)

  


  


  Trim all silence encountered from beginning to end where there is more
than 1 second of silence in audio :
silenceremove=stop_periods=-1:stop_duration=1:stop_threshold=-90dB

  


  


  I run this command

  


  ffmpeg -i my_file.mp3 -af silenceremove=stop_periods=-1:stop_threshold=-50dB:stop_duration=0.72 result1.mp3


  


  So, I am expecting that it should delete only the silence with "0.725917" duration (the last one in the above image), however it is deleting the silence that starts at 16.44s with duration of "0.714708"s. Please see the following comparison :

  


  

  


  4) Running detectsilence on result1.mp3 with same options gives even stranger results

  


  ffmpeg -i result1.mp3 -af silencedetect=noise=-50dB:d=0.2 -f null -


  


  result

  


  [mp3float @ 0000017723404280] overread, skip -5 enddists: -4 -4
[silencedetect @ 0000017723419540] silence_start: 6.21417
[silencedetect @ 0000017723419540] silence_end: 6.92462 | silence_duration: 0.710458
[mp3float @ 0000017723404280] overread, skip -7 enddists: -6 -6
[mp3float @ 0000017723404280] overread, skip -7 enddists: -2 -2
[mp3float @ 0000017723404280] overread, skip -6 enddists: -1 -1
    Last message repeated 1 times
[silencedetect @ 0000017723419540] silence_start: 23.7308
size=N/A time=00:00:24.45 bitrate=N/A speed=1.33e+03x
video:0kB audio:1146kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: unknown
[silencedetect @ 0000017723419540] silence_end: 24.456 | silence_duration: 0.725167


  


  So, the results are :

  


  

  • With command to remove silences that are longer than "0.72 second", a silence that was "0.714708"s, got removed and - a silence with "0.725917"s remained as is (well, actually changed a little - as per 3rd point)

  


  • The first silence that had started at "6.21417" and had a duration of "0.702958"s, suddenly now has a duration of "0.710458"s

  


  • The 3rd silence that had started at "24.4501" (which now starts at 23.7308 - obviously because the 2nd silence was removed) and had a duration of "0.725917", now suddenly is "0.725167"s (this one is not a big difference, but still why even removing other silence, this silence's duration should change at all).

  


  


  Accordingly the expected results are :

  


  

  • Only the silences that match the provided condition (stop_duration=0.72) should be removed. In this specific example only the last one, but in general any silence that matches the condition of the length - irrelevant of their positioning (start, end or in the middle)

  


  • Other silences should remain with same exact duration they were before

  


  


  FFMpeg : 4.2.4-1ubuntu0.1, Ubuntu : 20.04.2

  


  Some attempts and results, while playing with ffmpeg options

  


  a)

  


  ffmpeg -i my_file.mp3 -af silenceremove=stop_periods=-1:stop_threshold=-50dB:stop_duration=0.72:detection=peak tmp1.mp3


  


  result :
First and second silences are removed, 3rd silence's duration remains exactly the same

  


  b)

  


  ffmpeg -i my_file.mp3 -af silenceremove=stop_periods=-1:stop_threshold=-50dB:stop_duration=0.71 tmp_0.71.mp3


  


  result :
First and second silences are removed, 3rd silence remains, but the duration becomes "0.72075"s

  


  c)

  


  ffmpeg -i my_file.mp3 -af silenceremove=stop_periods=-1:stop_threshold=-50dB:stop_duration=0.7 tmp_0.7.mp3


  


  result :
all 3 silence are removed

  


  d) the edge case

  


  this command still removes the second silence (after which the first silence become exactly as in point #4 and last silence becomes "0.721375")

  


  ffmpeg -i my_file.mp3 -af silenceremove=stop_periods=-1:stop_threshold=-50dB:stop_duration=0.72335499999 tmp_0.72335499999.mp3


  


  but this one, again does not remove any silence :

  


  ffmpeg -i my_file.mp3 -af silenceremove=stop_periods=-1:stop_threshold=-50dB:stop_duration=0.723355 tmp_0.723355.mp3


  


  e) window param case 0.03

  


  ffmpeg -i my_file.mp3 -af silenceremove=stop_periods=-1:stop_threshold=-50dB:stop_duration=0.72:window=0.03 window_0.03.mp3


  


  does not remove any silence, but the detect silence

  


  ffmpeg -i window_0.03.mp3 -af silencedetect=noise=-50dB:d=0.2 -f null -


  


  gives this result (compare with silences in result1.mp3 - from point #4 )

  


  [mp3float @ 000001c5c8824280] overread, skip -5 enddists: -4 -4
[silencedetect @ 000001c5c883a040] silence_start: 6.21417
[silencedetect @ 000001c5c883a040] silence_end: 6.92462 | silence_duration: 0.710458
[mp3float @ 000001c5c8824280] overread, skip -7 enddists: -6 -6
[mp3float @ 000001c5c8824280] overread, skip -7 enddists: -2 -2
[silencedetect @ 000001c5c883a040] silence_start: 16.4424
[silencedetect @ 000001c5c883a040] silence_end: 17.1555 | silence_duration: 0.713167
[mp3float @ 000001c5c8824280] overread, skip -6 enddists: -1 -1
    Last message repeated 1 times
[silencedetect @ 000001c5c883a040] silence_start: 24.4508
size=N/A time=00:00:25.17 bitrate=N/A speed=1.24e+03x
video:0kB audio:1180kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: unknown
[silencedetect @ 000001c5c883a040] silence_end: 25.176 | silence_duration: 0.725167


  


  f) window case 0.01

  


  ffmpeg -i my_file.mp3 -af silenceremove=stop_periods=-1:stop_threshold=-50dB:stop_duration=0.72:window=0.01 window_0.01.mp3


  


  removes first and second silences, the detect silence with same params has the following result

  


  [mp3float @ 000001ea631d4280] overread, skip -5 enddists: -4 -4
    Last message repeated 1 times
[mp3float @ 000001ea631d4280] overread, skip -7 enddists: -2 -2
[mp3float @ 000001ea631d4280] overread, skip -6 enddists: -1 -1
    Last message repeated 1 times
[silencedetect @ 000001ea631ea1c0] silence_start: 23.0108
size=N/A time=00:00:23.73 bitrate=N/A speed=1.2e+03x
video:0kB audio:1113kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: unknown
[silencedetect @ 000001ea631ea1c0] silence_end: 23.736 | silence_duration: 0.725167


  


  ---

  


  Any thoughts, ideas, points are much appreciated.