2025.01.21

Tuesday, January 21, 2025

• Update all copyright notices to the year 2025.
• Simplify the description of the other-transcode.rb tool.
• Add a note to the "README" document regarding the project's current status.
• Begin using an updated date-based version numbering scheme.

0.12.0

Wednesday, October 12, 2022

• Modify other-transcode to explicitly set the output layout for AC-3 and Dolby Digital Plus (Enhanced AC-3) surround audio formats to six channels when the input has more than six channels, typically with 7.1 surround audio. Otherwise new versions of ffmpeg will only create five channels and drop the LFE channel. Via #167.

0.11.0

Saturday, July 16, 2022

• Modify other-transcode to copy 10-bit high-dynamic-range (HDR10) metadata, extracting content light level and mastering display metadata from a HDR10 video frame input and tagging a 10-bit video stream output in Matroska (MKV) format with that information. This will also copy static HDR10 metadata from Dolby Vision and HDR10+ video streams but it will not copy additional dynamic metadata from those formats.
• Add a --overlay-params option to other-transcode to override the overlay filter configuration applied when burning subtitles. This is useful when cropping to move a subtitle within the output boundary.
• Add a --fdk-vbr option to other-transcode to set the numeric variable bitrate (VBR) mode for the Fraunhofer libfdk_aac audio encoder, disabling constant bitrate (CBR) ratecontrol. VBR mode 1 selects the lowest quality and 5 the highest. Please note that the libfdk_aac encoder is not normally included with ffmpeg due to licensing restrictions and the --fdk-vbr option has no effect if that encoder is not available. Via #127.

0.10.0

Thursday, January 27, 2022

• Add a --nvenc-gpu-only option to other-transcode to keep data on the GPU for greater speed, if possible. Deinterlacing is allowed but cropping, scaling, detelecining, setting frame rates and burning subtitles will prevent this from working and may actually slow things down. Performance can also be affected negatively depending on PC configuration. Please note that the --nvenc-gpu-only option requires ffmpeg version 5.0 or later.
• Add a --x264-cbr option to other-transcode to simplify access to constant bitrate (CBR) ratecontrol. Despite the name, actual output bitrates from the x264 encoder are variable and below what might be expected. So, default video bitrate targets are raised to accommodate this.
• Enable proper crop detection in other-transcode for 4K UHD Blu-ray rips and other media with a 10-bit color depth. This was done by changing the limit value passed to the cropdetect filter from an integer constant to a floating point equation. Via #52.
• Modify other-transcode to add a workaround for the mapping of BT.470 M and BT.470 BG color transfer characteristics from values returned from ffprobe to values actually used by ffmpeg. Via #112.
• Modify other-transcode to allow parentheses within the argument to the --yadif-params, --x264-params and --x265-params options. Via #119.
• Modify ask-ffmpeg-log to fix detection of frame counts less than five digits within .log files from very short duration videos. Via #126.
• Modify ask-ffmpeg-log to fix detection of statistics within .log files not generated by other-transcode.
• Remove the deprecated --nvenc-rc-mode and --aac-stereo options from other-transcode.
• Update all copyright notices to the year 2022.

0.9.0

Saturday, June 5, 2021

Nvidia encoders:

• Add a --nvenc-recommended option to other-transcode which easily and optimally configures the Nvidia H.264 and HEVC video encoders, equivalent to using:
  • --nvenc-spatial-aq --nvenc-lookahead 32 --nvenc-bframe-refs middle
• The --nvenc-bframe-refs option is also new and using middle as its argument increases compression efficiency. However, it's not supported on all Nvidia hardware. Which means, neither is the --nvenc-recommended option.
• So, using --nvenc-recommended for H.264 encoding requires at minimum a fourth generation Pascal-based GPU like the GTX 1080. And using it for HEVC encoding requires at minimum a more recent sixth generation Turing-based model like the GTX 1660 or RTX 2070.
• Add a --nvenc-cq option to other-transcode to allow constant quality (CQ) ratecontrol. This option ignores the target video bitrate and takes a single numerical argument between 1 and 51 with lower values indicating higher quality. However, only values between 25 and 30 are really practical for 1080p content. It's recommended to start with --nvenc-cq 28 and adjust as needed. Fractional values are also supported.
• While CQ ratecontrol can adapt better to extremely dynamic content compared to the default average bitrate (ABR) ratecontrol system, the output bitrates produced by CQ can vary significantly and it can be slightly more prone to color banding with the H.264 encoder. So, for now, consider the --nvenc-cq option an experimental feature.
• Deprecate the --nvenc-rc-mode option in other-transcode because maximum rate and buffer size values are already specified so an explicit ratecontrol mode is not required.

Audio:

• Modify other-transcode to no longer explicitly set audio bitrates and instead rely on the defaults from the audio encoders included with ffmpeg. This is being done to both simplify the code in other-transcode and to leverage the judgement of the audio encoder developers, which means:
  • AC-3 surround audio is lowered from 640 Kbps to 448 Kbps.
  • Dolby Digital Plus (Enhanced AC-3) surround audio is raised from 384 Kbps to 448 Kbps.
  • AAC stereo audio is lowered from 256 Kbps to 128 Kbps when using the native ffmpeg or Apple AudioToolbox encoders.
• If desired, use the --surround-bitrate and --stereo-bitrate options to restore the previous default audio bitrates.
• Add a --aac-only option to other-transcode to force transcoding of all audio into AAC format, copying only tracks which are already in that format. Surround tracks are converted to a 5.1-channel AAC format at 341 Kbps when using the native ffmpeg encoder. This channel layout is compatible with most playback devices. Allowing more than 5.1 channels would significantly reduce playback compatibility.
• Deprecate the --aac-stereo option in other-transcode and replace with a new --eac3-aac option, which uses Dolby Digital Plus format only for surround audio with AAC format for stereo audio. Since the --aac-stereo option only made sense when used in combination with the --eac3 option, this makes --eac3-aac more convenient.

Other changes:

• Change the default ratecontrol maximum rate and buffer size values in other-transcode, as well as how those values increased when the target video bitrate is increased. The default values now also differ depending on whether the output video is in H.264 or HEVC format.
• Modify the --rc-maxrate and --rc-bufsize options in other-transcode to allow specific bitrates as arguments and not just multiples of the video bitrate target. These options are most useful for lowering maximum rate and buffer size values. To raise those values, increase the target video bitrate instead.
• Change the pixel format and force a Main 10 video profile in other-transcode when using the Apple VideoToolbox encoder to create output with a 10-bit color depth. Correct generation of 10-bit output requires macOS Big Sur or later.
• Modify other-transcode to copy the three basic color properties (primaries, transer and space) from the input to the output when those properties are availabe. Otherwise use some sensible defaults.
• Modify other-transcode to force a H.264 level when using --x264 with slower presets. This ensures that the x264 encoder continues to generate a video stream compatible with most playback devices when those presets are used.
• Modify other-transcode to remove the hack which avoids using the Matroksa muxer -disposition option in old versions of ffmpeg. This means version 4.3 or later of ffmpeg is now required to run other-transcode.

0.8.0

Saturday, February 13, 2021

• Modify other-transcode to:
  • No longer automatically deinterlace video with a frame rate of 29.97 FPS.
  • No longer change the frame rate of any video in MPEG-2 format which was automatically deinterlaced.
  • Only automatically deinterlace non-progressive video.
  • Apply any automatic or explicit deinterlacing to all frames of the video, not just the interlaced frames.
  • Force a constant frame rate for any video in MPEG-2 format at 29.97 FPS.
• Add a --yadif-params option to other-transcode to allow customization of the yadif filter used for deinterlacing.
• Remove the deprecated --all-eac3 option of other-transcode.

0.7.0

Monday, January 4, 2021

• Modify other-transcode to lower default target bitrates in order to significantly reduce the size of transcoded output at the risk of a slight reduction in perceived quality. Via #89.

H.264 video:

Resolution	old	new
1080p (Blu-ray video)	8000 Kbps	6000 Kbps
720p	4000 Kbps	3000 Kbps
480p (DVD video)	2000 Kbps	1500 Kbps

HEVC video:

Resolution	old	new
1080p (Blu-ray video)	6000 Kbps	4000 Kbps
720p	3000 Kbps	2000 Kbps
480p (DVD video)	1500 Kbps	1000 Kbps

Dolby Digital Plus (Enhanced AC-3) audio:

Channels	old	new
Surround	640 Kbps	384 Kbps
Stereo	256 Kbps	192 Kbps
Mono	128 Kbps	96 Kbps

Note: There are no changes to default target bitrates for Dolby Digital (AC-3) and AAC audio formats.

• Change the --eac3 option in other-transcode to use Dolby Digital Plus format for all transcoded audio instead of just surround output.
• Deprecate the --all-eac3 option in other-transcode since the --eac3 option now has the same behavior.
• Add a --aac-stereo option to other-transcode. This uses AAC format for transcoded stereo audio output so it can be paired with --eac3 to get that option's old behavior.
• Add a --8-bit-vc1 option. When the color depth is currently 10-bit, this option uses an 8-bit color depth for video inputs in VC-1 format only.

0.6.0

Tuesday, December 22, 2020

• Lower the default target bitrates for 8-bit HEVC video in other-transcode to match the defaults for 10-bit HEVC video. This means, for example, the default target for HEVC at a 1080p resolution will be 6000 Kbps no matter the output bit depth.
• Modify other-transcode to set the video buffer size equal to the maximum video bitrate when using an Nvidia encoder, essentially adding --rc-bufsize 3 to the command line. Previously the buffer size was never explicitly set so ffmpeg would use a default value of twice the target bitrate. Since the maximum bitrate is normally three times the target bitrate this meant the buffer size was actually smaller than the maximum. While this didn't cause any known problems, Nvidia recommends a larger buffer size to improve quality. However, using --rc-bufsize 0 will restore the old behavior and the default value from ffmpeg.
• Ignore the --nvenc-lookahead option in other-transcode when the argument is 0 since such a value won't change the behavior of an Nvidia encoder anyway.
• Add a --limit-ac3-surround option to other-transcode which prevents surround audio in AC-3 or Dolby Digital Plus (Enhanced AC-3) format from being copied instead of transcoded when the orginal bitrate is above the transcoding bitrate. This allows setting a lower target with the --surround-bitrate option in order to force higher-bitrate tracks to be transcoded instead of copied.
• Reduce the minimum bitrates for Dolby Digital Plus audio in other-transcode from 256, 128 and 64 Kbps for surround, stereo and mono layouts to 192, 96 and 48 Kbps. The default bitrates for Dolby Digital Plus audio remain the same and this change does not affect audio output in AC-3 or AAC formats.

0.5.0

Tuesday, November 24, 2020

• Add --qsv-decoder and --qsv-device options to other-transcode, both of which enable the scoped use of the Intel Quick Sync Video (QSV) decoder instead of the generic hardware decoder. These options can significantly speed operation of the QSV encoder, invoked via --qsv. It's recommended that --decode all be included when using these options to decode all video input formats. The --qsv-device option allows selection of specific hardware by number or path depending on platform. Please note that deinterlacing, cropping, scaling or using other filters will disable QSV's format-specific decoders.
• Remove all deprecated options and arguments from other-transcode.

0.4.0

Sunday, November 1, 2020

• Modify the behavior and augment the capabilities of both encoding and decoding when using Nvidia hardware with other-transcode. This is necessary for compatibility with unleased versions of ffmpeg which are now built using the new Nvidia Software Development Kit (SDK) version 11.0. This SDK changes default encoder behavior and adds new presets which allow finer control of the performance/quality trade-off when transcoding video. To allow maximum performance, other-transcode no longer enables some quality settings by default:
  • Multipass mode, now accessible via a new --nvenc-multipass option. Be advised that any improved quality from enabling multipass mode is probably not worth the performance impact.
  • Spatial and temporal adaptive quantization (AQ), accessible via the --nvenc-spatial-aq and --nvenc-temporal-aq options. While enabling spatial AQ is still useful in reducing color banding for some inputs, be advised that enabling temporal AQ is probably not necessary and can cause some other side effects.
• Add support for seven new Nvidia encoder presets to other-transcode. Use --preset p1 for best performance and --preset p7 for best quality. It's not necessary to use --preset p4 since that's the default. See the Nvidia preset migration guide to understand how these presets work and how they map to older behavior.
• Add a --nvenc-rc-mode option to other-transcode for backward comaptibility with ffmpeg version 4.3.1 and older.
• Add --cuda and --no-cuda options to other-transcode. These options enable or disable the scoped use of the Nvidia CUDA hardware decoder instead of the generic hardware decoder. By default the CUDA decoder is enabled when using the Nvidia video encoder, but disabled when using other encoders.
• Deprecate the --cuvid option in other-transcode because the CUDA decoder is faster and more flexible.
• Deprecate --preset none in other-transcode because it's no longer necessary.
• Always use hyphen-based spellings of Nvidia AQ options in ffmpeg commands generated by other-transcode.
• Add --x264-params and --x265-params options to other-transcode for very advanced manipulation of the x264 and x265 software encoders.
• Modify other-transcode to assume a video input without a field_order tag is progressive instead of interlaced so a deinterlace fliter is not automatically and incorrectly applied to that video. This avoids problems with some 4K Ultra HD Blu-ray rips.
• Update the link to Docker containers for Linux in the "README" document. Thanks, @ttyS0!