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• ffmpeg - MXF with 4-channel audio : how to create proxies (high quality / small file size) and preserve the audio mapping

  8 juillet 2018, par WhatsYourFunction

  We’ve got MXF sources (h.264 video at UHD (3840x2160) with 4-channels of (4 - PCM S24 mono sources)
  We want Proxies — smallest file size at highest picture quality
  The compression applied to the video and audio essences can be anything,
  And the wrapper can be either MXF or QuickTime
  but we need to preserve the audio mapping (i.e. the Proxy must be 4-channel audio)

  How to do that with ffmpeg ?

  • EDIT Adding ffprobe :

  Metadata :

  uid : ***

  generation_uid : ***

  company_name : CANON

  product_name : EOS C300 Mark II

  product_version : 1.00

  product_uid : ***

  modification_date : 2018-06-28T08:29:24.000000Z

  material_package_umid : ***

  timecode : 02:50:31:17

  Duration : 00:06:35.40, start : 0.000000, bitrate : 395842 kb/s

  Stream #0:0 : Video : h264 (High 4:2:2 Intra), yuv422p10le(tv, progressive), 3840x2160, SAR 1:1 DAR 16:9, 23.98 fps, 23.98 tbr, 23.98 tbn, 47.95 tbc

  Metadata :

   file_package_umid: ***

  Stream #0:1 : Audio : pcm_s24le, 48000 Hz, 1 channels, s32 (24 bit), 1152 kb/s

  Metadata :

   file_package_umid: ***

  Stream #0:2 : Audio : pcm_s24le, 48000 Hz, 1 channels, s32 (24 bit), 1152 kb/s

  Metadata :

   file_package_umid: ***

  Stream #0:3 : Audio : pcm_s24le, 48000 Hz, 1 channels, s32 (24 bit), 1152 kb/s

  Metadata :

   file_package_umid: ***

  Stream #0:4 : Audio : pcm_s24le, 48000 Hz, 1 channels, s32 (24 bit), 1152 kb/s

  Metadata :

   file_package_umid: ***

• How to set H264 NVENC encoding parameters to output high-quality video stream ?

  8 février 2021, par fredirty2017
  

  • I use NVENC (nvEncodeAPI) interface hardware encoding H264, and then RTMP to stream out, when using ffplay to pull the stream to watch, I found that the picture is obviously distorted : the green lines become sharper ? the text color becomes lighter and blurred, it is not improved even if I increase the video bitrate to 3Mbps(720P). I also know that H264 encoding is lossy, and some information will be discarded.

  


  • Then I try to adjust the NV_ENC_CONFIG_H264_VUI_PARAMETERS parameter : when set color-space to "pc, bt709", there are some minor improvements. Maybe the color-space setting has more potential for improvement ? For NVENC encoding, is there a higher video clarity setting scheme ? I don't know how much space for technical improvement is here ?

based on the code : https://github.com/obsproject/obs-studio/blob/master/plugins/obs-ffmpeg/obs-ffmpeg-nvenc.c

  


  


• FFmpeg : High pitched audio when converting AVI video to MP4 [closed]

  15 août 2023, par Karen S

  I'm pretty new to FFmpeg and I'm having trouble converting a video from AVI format to MP4. I'm trying to convert pcm_s16le to aac but the resulting audio is very high pitched and choppy.

  


  The AVI video has two audio streams :

  


  Stream #0:1: Audio: pcm_s16le, 48000 Hz, stereo, s16, 1536 kb/s
Stream #0:2: Audio: pcm_s16le, 32000 Hz, stereo, s16, 1024 kb/s


  


  In VLC Media Player the video plays fine and it uses the second audio stream.

  


  When I run ffmpeg -i input.avi -vcodec libx264 -crf 27 output.mp4 in my terminal, the output audio in the MP4 file sounds extremely choppy and the voices are chipmunk-like.
This is the codec information for the audio stream in VLC after the conversion :

  


  Codec: MPEG AAC Audio (mp4a)
Type: Audio
Channels: Stereo
Sample rate: 48000 Hz
Bits per sample: 32


  


  This is the terminal output :

  


  ffmpeg version 2023-06-11-git-09621fd7d9-full_build-www.gyan.dev Copyright (c) 2000-2023 the FFmpeg developers
  built with gcc 12.2.0 (Rev10, Built by MSYS2 project)
  configuration: --enable-gpl --enable-version3 --enable-static --disable-w32threads --disable-autodetect --enable-fontconfig --enable-iconv --enable-gnutls --enable-libxml2 --enable-gmp --enable-bzlib --enable-lzma --enable-libsnappy --enable-zlib --enable-librist --enable-libsrt --enable-libssh --enable-libzmq --enable-avisynth --enable-libbluray --enable-libcaca --enable-sdl2 --enable-libaribb24 --enable-libaribcaption --enable-libdav1d --enable-libdavs2 --enable-libuavs3d --enable-libzvbi --enable-librav1e --enable-libsvtav1 --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxavs2 --enable-libxvid --enable-libaom --enable-libjxl --enable-libopenjpeg --enable-libvpx --enable-mediafoundation --enable-libass --enable-frei0r --enable-libfreetype --enable-libfribidi --enable-liblensfun --enable-libvidstab --enable-libvmaf --enable-libzimg --enable-amf --enable-cuda-llvm --enable-cuvid --enable-ffnvcodec --enable-nvdec --enable-nvenc --enable-d3d11va --enable-dxva2 --enable-libvpl --enable-libshaderc --enable-vulkan --enable-libplacebo --enable-opencl --enable-libcdio --enable-libgme --enable-libmodplug --enable-libopenmpt --enable-libopencore-amrwb --enable-libmp3lame --enable-libshine --enable-libtheora --enable-libtwolame --enable-libvo-amrwbenc --enable-libcodec2 --enable-libilbc --enable-libgsm --enable-libopencore-amrnb --enable-libopus --enable-libspeex --enable-libvorbis --enable-ladspa --enable-libbs2b --enable-libflite --enable-libmysofa --enable-librubberband --enable-libsoxr --enable-chromaprint
  libavutil      58. 13.100 / 58. 13.100
  libavcodec     60. 17.100 / 60. 17.100
  libavformat    60.  6.100 / 60.  6.100
  libavdevice    60.  2.100 / 60.  2.100
  libavfilter     9.  8.101 /  9.  8.101
  libswscale      7.  3.100 /  7.  3.100
  libswresample   4. 11.100 /  4. 11.100
  libpostproc    57.  2.100 / 57.  2.100
[avi @ 000001d1b05ffbc0] Switching to NI mode, due to poor interleaving
Input #0, avi, from 'VG2002-06-10 TAPE_71 001.avi':
  Duration: 00:10:40.64, start: 0.000000, bitrate: 28852 kb/s
  Stream #0:0: Video: dvvideo, yuv411p, 720x480 [SAR 32:27 DAR 16:9], 25000 kb/s, SAR 8:9 DAR 4:3, 60k fps, 29.97 tbr, 60k tbn
  Stream #0:1: Audio: pcm_s16le, 48000 Hz, stereo, s16, 1536 kb/s
  Stream #0:2: Audio: pcm_s16le, 32000 Hz, stereo, s16, 1024 kb/s
File 'VG2002-06-10compress.mp4' already exists. Overwrite? [y/N] y
Stream mapping:
  Stream #0:0 -> #0:0 (dvvideo (native) -> h264 (libx264))
  Stream #0:1 -> #0:1 (pcm_s16le (native) -> aac (native))
Press [q] to stop, [?] for help
[pcm_s16le @ 000001d1b0696680] This decoder does not support parameter changes, but PARAM_CHANGE side data was sent to it.
[pcm_s16le @ 000001d1b0696680] Error applying parameter changes.
[libx264 @ 000001d1b0ab4940] using SAR=8/9
[libx264 @ 000001d1b0ab4940] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 AVX FMA3 BMI2 AVX2
[libx264 @ 000001d1b0ab4940] profile High 4:2:2, level 3.0, 4:2:2, 8-bit
[libx264 @ 000001d1b0ab4940] 264 - core 164 r3107 a8b68eb - H.264/MPEG-4 AVC codec - Copyleft 2003-2023 - 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=12 lookahead_threads=2 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=27.0 qcomp=0.60 qpmin=0 qpmax=69 qpstep=4 ip_ratio=1.40 aq=1:1.00
Output #0, mp4, to 'VG2002-06-10compress.mp4':
  Metadata:
    encoder         : Lavf60.6.100
  Stream #0:0: Video: h264 (avc1 / 0x31637661), yuv422p(tv, bottom coded first (swapped)), 720x480 [SAR 8:9 DAR 4:3], q=2-31, 29.97 fps, 30k tbn
    Metadata:
      encoder         : Lavc60.17.100 libx264
    Side data:
      cpb: bitrate max/min/avg: 0/0/0 buffer size: 0 vbv_delay: N/A
  Stream #0:1: Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 128 kb/s
    Metadata:
      encoder         : Lavc60.17.100 aac
[dvvideo @ 000001d1b0a26f00] Concealing bitstream errors.49 bitrate=1424.2kbits/s speed=2.51x
    Last message repeated 76 times
[dvvideo @ 000001d1b0f61680] Concealing bitstream errors.23 bitrate=1451.5kbits/s speed=2.47x
    Last message repeated 19 times
[out#0/mp4 @ 000001d1b0696c80] video:106080kB audio:6745kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 0.465412%
frame=19200 fps= 73 q=-1.0 Lsize=  113351kB time=00:10:40.60 bitrate=1449.5kbits/s speed=2.43x
[libx264 @ 000001d1b0ab4940] frame I:99    Avg QP:26.85  size: 42388
[libx264 @ 000001d1b0ab4940] frame P:4922  Avg QP:29.69  size: 13724
[libx264 @ 000001d1b0ab4940] frame B:14179 Avg QP:33.82  size:  2601
[libx264 @ 000001d1b0ab4940] consecutive B-frames:  1.2%  0.8%  1.1% 97.0%
[libx264 @ 000001d1b0ab4940] mb I  I16..4: 12.2% 77.3% 10.4%
[libx264 @ 000001d1b0ab4940] mb P  I16..4:  1.7%  8.1%  1.4%  P16..4: 39.9% 16.6% 12.2%  0.0%  0.0%    skip:20.1%
[libx264 @ 000001d1b0ab4940] mb B  I16..4:  0.3%  0.6%  0.1%  B16..8: 38.6%  3.8%  1.1%  direct: 3.3%  skip:52.2%  L0:42.2% L1:49.3% BI: 8.5%
[libx264 @ 000001d1b0ab4940] 8x8 transform intra:71.6% inter:71.6%
[libx264 @ 000001d1b0ab4940] coded y,uvDC,uvAC intra: 72.3% 66.8% 11.7% inter: 17.3% 10.6% 0.2%
[libx264 @ 000001d1b0ab4940] i16 v,h,dc,p: 11% 64%  7% 17%
[libx264 @ 000001d1b0ab4940] i8 v,h,dc,ddl,ddr,vr,hd,vl,hu: 11% 26% 24%  5%  6%  5%  9%  5%  9%
[libx264 @ 000001d1b0ab4940] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu:  8% 52% 13%  3%  5%  4%  7%  3%  6%
[libx264 @ 000001d1b0ab4940] i8c dc,h,v,p: 58% 21% 17%  5%
[libx264 @ 000001d1b0ab4940] Weighted P-Frames: Y:3.5% UV:1.3%
[libx264 @ 000001d1b0ab4940] ref P L0: 51.9% 15.0% 23.5%  9.3%  0.3%
[libx264 @ 000001d1b0ab4940] ref B L0: 87.5%  9.7%  2.9%
[libx264 @ 000001d1b0ab4940] ref B L1: 95.1%  4.9%
[libx264 @ 000001d1b0ab4940] kb/s:1356.46
[aac @ 000001d1b0a6ab80] Qavg: 517.695


  


  FFmpeg automatically selects the first audio stream to encode but then this error comes up :

  


  [pcm_s16le @ 000001d1b0696680] This decoder does not support parameter changes, but PARAM_CHANGE side data was sent to it.


  


  To bypass this error, I've edited the FFmpeg command so that the second stream is selected instead for aac encoding, but then the resulting MP4 video is silent.

  


  Does anyone know why FFmpeg is unable to convert the original AVI audio to aac without it sounding higher-pitched ? I think that the sample rate of the first stream might be set incorrectly but I'm not too sure how to fix it so that the encoder reads it properly.