doc:appunti:linux:video:ffmpeg_final_rendering
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doc:appunti:linux:video:ffmpeg_final_rendering [2023/11/13 12:38] – [Encoding for High Definition Video] niccolo | doc:appunti:linux:video:ffmpeg_final_rendering [2024/07/31 09:57] (current) – [Two pass encoding] niccolo | ||
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- | ====== Final Rendering | + | ====== Final Rendering with libx264 and ffmpeg ====== |
Whether you are working with **Ffmepg**, **Avidemux** or **Olive Video Editor**, you should be wondering what parameters to use to final render a video montage. Here are my choices for some specific purpose. | Whether you are working with **Ffmepg**, **Avidemux** or **Olive Video Editor**, you should be wondering what parameters to use to final render a video montage. Here are my choices for some specific purpose. | ||
- | |||
===== Encoding for High Definition Video ===== | ===== Encoding for High Definition Video ===== | ||
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^ Basic x264 | Preset: **slow** (or less), Tuning: **film**, Profile: **High**, IDC Level: **Auto** | | ^ Basic x264 | Preset: **slow** (or less), Tuning: **film**, Profile: **High**, IDC Level: **Auto** | | ||
^ Video encoding | ^ Video encoding | ||
- | ^ Pixel format | + | ^ Pixel format |
^ Bits per sample | ^ Bits per sample | ||
- | ^ Color range | We use the **full range** of colors. The **j** letter in the // | + | ^ Color range | We use the **full range** of colors. The **j** letter in the // |
^ Audio codec | < | ^ Audio codec | < | ||
^ Audio bitrate | ^ Audio bitrate | ||
Line 36: | Line 35: | ||
-filter:v " | -filter:v " | ||
-vcodec ' | -vcodec ' | ||
+ | -b:v 4M -maxrate:v 6M -bufsize:v 6M \ | ||
-acodec copy \ | -acodec copy \ | ||
" | " | ||
</ | </ | ||
+ | |||
+ | Notice that we selected a target bitrate of **4 Mbps** and a maximum bitrate of **6 Mbps**. Sepcifying both the //bitrate// and the //max bitrate tolerance// requires also to specify a //buffer size//; '' | ||
+ | |||
+ | ===== A warning about the H.264 profile level ===== | ||
+ | |||
+ | It turned out that **Kodi 19.4** (running on a Raspberry Pi 4 with **Raspbian GNU/Linux 11 Bullseye** o.s.) has some problems playing H.264 video files depending on the video format profile used for the encoding. The video actually starts to play, but nothing is seen on the screen; sometimes the screen goes totally green. Similarly a **Google TV** with Kodi 21.0 has problems with the same files, showing stuttering and video artifacts. | ||
+ | |||
+ | Here it is a table of playing capabilities based on experimental testing: | ||
+ | |||
+ | ^ Format profile | ||
+ | | High@L5 | ||
+ | | High@L4 | ||
+ | | High@L4.1 | ||
+ | | High@5 | ||
+ | | High@5 | ||
+ | |||
+ | ===== Two pass encoding ===== | ||
+ | |||
+ | Here it is a recipe of **two-pass encoding** from an high quality //master// produced with [[olive_editor_tools# | ||
+ | |||
+ | <code bash> | ||
+ | TITLE=' | ||
+ | ffmpeg \ | ||
+ | -i full32bit-veryslow-crf18-fullcolor.mkv \ | ||
+ | -metadata title=" | ||
+ | -vcodec ' | ||
+ | -profile:v ' | ||
+ | -b:v 6M -maxrate:v 9M -bufsize:v 18M \ | ||
+ | -x264-params ' | ||
+ | -an \ | ||
+ | -pass 1 \ | ||
+ | -f matroska -y /dev/null | ||
+ | # First pass produces two files: ffmpeg2pass-0.log and ffmpeg2pass-0.log.mbtree. | ||
+ | ffmpeg \ | ||
+ | -i full32bit-veryslow-crf18-fullcolor.mkv \ | ||
+ | -metadata title=" | ||
+ | -vcodec ' | ||
+ | -profile:v ' | ||
+ | -b:v 6M -maxrate:v 9M -bufsize:v 18M \ | ||
+ | -x264-params ' | ||
+ | -an \ | ||
+ | -pass 2 \ | ||
+ | -f matroska marocco-twopass-6max9-level41.mkv | ||
+ | </ | ||
+ | |||
+ | The transcoding works on the video only, suppressing any audio stream (**%%-an%%** option). Using the **keyint=64** option will produce a keyframe every 64 frames (about two seconds), this make seeking back and forward in the video more smooth. | ||
===== Pixel format considerations ===== | ===== Pixel format considerations ===== |
doc/appunti/linux/video/ffmpeg_final_rendering.1699875532.txt.gz · Last modified: 2023/11/13 12:38 by niccolo