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• torchaudio.io.StreamReader doesn't throw error when seeking to time stamp more than the duration of audio file

  27 mars 2023, par lokesh

  I am trying to get the audio chunk of audio file between specific start time and end time

  


  Consider a audio of duration 10 seconds. Now i need to get chunk from 4 sec to 7 sec

  


  torchaudio.info doesn't give correct num_frames for io.BytesIO flac audio file. So there is no way to find the total number of frames in the given audio to check for out of bounds start offset
Ref : https://github.com/pytorch/audio/issues/2524

  


  What I did to get the chunk of audio with start and end offsets.

  


  def read_audio(audio_file, start, end):
    audio_file.seek(0)
    reader = StreamReader(audio_file)
    sample_rate = int(reader.get_src_stream_info(reader.default_audio_stream).sample_rate)

    reader.seek(start * sample_rate)
    reader.add_basic_audio_stream(frames_per_chunk=(end - start) * sample_rate)

    return list(reader.stream())[0].pop()


  


  This is working as intended for start time less than the duration of audio file. But when we give the start time more than the duration of audio file, It doesn't throw error or return empty tensor.
Is there any way to know the given offsets are out of bounds.

  


• PHP-FFMpeg filters()->resize() throw Use of undefined constant RESIZEMODE_INSET

  27 février 2023, par Angus Simons

  I'm using PHP-FFMpeg to use FFMpeg with php, unfortunately I can't set resize filter.

  



  This is my code :

  



  $video = $ffmpeg->open('video.mov');

$dimension = new FFMpeg\Coordinate\Dimension(1920, 1080);
$video->filters()
      ->resize($dimension, RESIZEMODE_INSET, true, 1)
      ->synchronize();

$format = new FFMpeg\Format\Video\X264('aac', 'libx264');
$format->setAudioChannels(2)->setAudioKiloBitrate(256);
$video->save($format, 'video.mp4');


  



  But it throws this error :

  



  Use of undefined constant RESIZEMODE_INSET - assumed 'RESIZEMODE_INSET'

  



  I tried also :

  



  ->resize($dimension, 'RESIZEMODE_INSET', true, 1)

  



  and

  



  ->resize($dimension, 'inset', true, 1)

  



  But I can't get the video converted without stretching.

  



  Thanks in advance

  


• ffmpeg throw a silent video output when trying to merge video and audio

  31 janvier 2023, par porororo

  I tried to combine mp4 format video and wav format audio.
The video is shorter than the audio and start second is same as 00:00.

  


  I used command as bellows :

  


  ffmpeg -i video.mp4 -i audio.wav  -filter_complex "[0:a]volume=0.2[A];[1:a][A]amerge[Aout]" -map 0:v -map [Aout] -y -shortest output_video.mp4


  


  The problem is the output_video.mp4 is a silent video without the sound.

  


  How can I get the output_video.mp4 with sound from audio.wav ?

  


  ffmpeg output is :

  


  

ffmpeg version 4.2.2 Copyright (c) 2000-2019 the FFmpeg developers
built with gcc 7.3.0 (crosstool-NG 1.23.0.449-a04d0)
configuration: --prefix=/tmp/build/80754af9/ffmpeg_1587154242452/\_h_env_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placeho --cc=/tmp/build/80754af9/ffmpeg_1587154242452/\_build_env/bin/x86_64-conda_cos6-linux-gnu-cc --disable-doc --enable-avresample --enable-gmp --enable-hardcoded-tables --enable-libfreetype --enable-libvpx --enable-pthreads --enable-libopus --enable-postproc --enable-pic --enable-pthreads --enable-shared --enable-static --enable-version3 --enable-zlib --enable-libmp3lame --disable-nonfree --enable-gpl --enable-gnutls --disable-openssl --enable-libopenh264 --enable-libx264
libavutil      56. 31.100 / 56. 31.100
libavcodec     58. 54.100 / 58. 54.100
libavformat    58. 29.100 / 58. 29.100
libavdevice    58.  8.100 / 58.  8.100
libavfilter     7. 57.100 /  7. 57.100
libavresample   4.  0.  0 /  4.  0.  0
libswscale      5.  5.100 /  5.  5.100
libswresample   3.  5.100 /  3.  5.100
libpostproc    55.  5.100 / 55.  5.100
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'video.mp4':
Metadata:
major_brand     : isom
minor_version   : 512
compatible_brands: isomiso2avc1mp41
encoder         : Lavf58.29.100
Duration: 00:00:19.04, start: 0.000000, bitrate: 510 kb/s
Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 1280x720, 373 kb/s, 30 fps, 30 tbr, 15360 tbn, 60 tbc (default)
Metadata:
handler_name    : VideoHandler
Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz, stereo, fltp, 128 kb/s (default)
Metadata:
handler_name    : SoundHandler
Guessed Channel Layout for Input Stream #1.0 : mono
Input #1, wav, from 'audio.wav':
Duration: 00:00:14.70, bitrate: 352 kb/s
Stream #1:0: Audio: pcm_s16le (\[1\]\[0\]\[0\]\[0\] / 0x0001), 22050 Hz, mono, s16, 352 kb/s
Stream mapping:
Stream #0:1 (aac) -\> volume (graph 0)
Stream #1:0 (pcm_s16le) -\> amerge:in0 (graph 0)
Stream #0:0 -\> #0:0 (h264 (native) -\> h264 (libx264))
amerge (graph 0) -\> Stream #0:1 (aac)
Press \[q\] to stop, \[?\] for help
\[libx264 @ 0x55aa9a642ac0\] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 AVX FMA3 BMI2 AVX2 AVX512
\[libx264 @ 0x55aa9a642ac0\] profile High, level 3.1, 4:2:0, 8-bit
\[libx264 @ 0x55aa9a642ac0\] 264 - core 157 - H.264/MPEG-4 AVC codec - Copyleft 2003-2018 - http://www.videolan.org/x264.html - options: cabac=1 ref=3 deblock=1:0:0 analyse=0x3:0x113 me=hex subme=7 psy=1 psy_rd=1.00:0.00 mixed_ref=1 me_range=16 chroma_me=1 trellis=1 8x8dct=1 cqm=0 deadzone=21,11 fast_pskip=1 chroma_qp_offset=-2 threads=22 lookahead_threads=3 sliced_threads=0 nr=0 decimate=1 interlaced=0 bluray_compat=0 constrained_intra=0 bframes=3 b_pyramid=2 b_adapt=1 b_bias=0 direct=1 weightb=1 open_gop=0 weightp=2 keyint=250 keyint_min=25 scenecut=40 intra_refresh=0 rc_lookahead=40 rc=crf mbtree=1 crf=23.0 qcomp=0.60 qpmin=0 qpmax=69 qpstep=4 ip_ratio=1.40 aq=1:1.00
\[Parsed_amerge_1 @ 0x55aa9b37c140\] No channel layout for input 1
Output #0, mp4, to 'output_video.mp4':
Metadata:
major_brand     : isom
minor_version   : 512
compatible_brands: isomiso2avc1mp41
encoder         : Lavf58.29.100
Stream #0:0(und): Video: h264 (libx264) (avc1 / 0x31637661), yuv420p(progressive), 1280x720, q=-1--1, 30 fps, 15360 tbn, 30 tbc (default)
Metadata:
handler_name    : VideoHandler
encoder         : Lavc58.54.100 libx264
Side data:
cpb: bitrate max/min/avg: 0/0/0 buffer size: 0 vbv_delay: -1
Stream #0:1: Audio: aac (LC) (mp4a / 0x6134706D), 22050 Hz, 3.0, fltp, 197 kb/s (default)
Metadata:
encoder         : Lavc58.54.100 aac
frame=  507 fps=291 q=-1.0 Lsize=    1116kB time=00:00:16.80 bitrate= 544.3kbits/s speed=9.64x  
video:760kB audio:342kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 1.242977%
\[libx264 @ 0x55aa9a642ac0\] frame I:3     Avg QP:16.24  size: 19770
\[libx264 @ 0x55aa9a642ac0\] frame P:154   Avg QP:20.29  size:  3227
\[libx264 @ 0x55aa9a642ac0\] frame B:350   Avg QP:19.84  size:   633
\[libx264 @ 0x55aa9a642ac0\] consecutive B-frames:  0.6% 15.8% 18.9% 64.7%
\[libx264 @ 0x55aa9a642ac0\] mb I  I16..4: 23.5% 67.4%  9.1%
\[libx264 @ 0x55aa9a642ac0\] mb P  I16..4:  0.7%  3.0%  0.3%  P16..4: 13.0%  3.1%  1.0%  0.0%  0.0%    skip:78.8%
\[libx264 @ 0x55aa9a642ac0\] mb B  I16..4:  0.2%  0.1%  0.0%  B16..8: 10.4%  0.3%  0.0%  direct: 0.6%  skip:88.3%  L0:41.5% L1:57.2% BI: 1.3%
\[libx264 @ 0x55aa9a642ac0\] 8x8 transform intra:68.2% inter:81.9%
\[libx264 @ 0x55aa9a642ac0\] coded y,uvDC,uvAC intra: 24.6% 22.9% 6.1% inter: 1.2% 1.7% 0.0%
\[libx264 @ 0x55aa9a642ac0\] i16 v,h,dc,p: 68% 16%  6% 10%
\[libx264 @ 0x55aa9a642ac0\] i8 v,h,dc,ddl,ddr,vr,hd,vl,hu: 24% 10% 50%  2%  2%  3%  2%  4%  3%
\[libx264 @ 0x55aa9a642ac0\] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 32% 25% 13%  5%  5%  6%  5%  6%  4%
\[libx264 @ 0x55aa9a642ac0\] i8c dc,h,v,p: 75% 10% 12%  2%
\[libx264 @ 0x55aa9a642ac0\] Weighted P-Frames: Y:0.0% UV:0.0%
\[libx264 @ 0x55aa9a642ac0\] ref P L0: 65.9% 16.2% 13.5%  4.4%
\[libx264 @ 0x55aa9a642ac0\] ref B L0: 84.1% 13.4%  2.5%
\[libx264 @ 0x55aa9a642ac0\] ref B L1: 97.1%  2.9%
\[libx264 @ 0x55aa9a642ac0\] kb/s:368.24
\[aac @ 0x55aa9a62a280\] Qavg: 8290.713