Differences

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--- doc:appunti:linux:video:ffmpeg_final_rendering [2024/07/31 09:53] – [Two pass encoding] niccolo
+++ doc:appunti:linux:video:ffmpeg_final_rendering [2024/07/31 09:57] (current) – [Two pass encoding] niccolo
@@ Line 41: / Line 41: @@
 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//; ''ffmpeg'' will re-adjust the bitrate on each buffer size, so if the buffer size is equal to the max rate, ffmpeg will re-calculate the bitrate at least every second.
+=====  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  ^ Resolution   ^ Mbps  ^ Can play on Kodi  ^
+| High@L5         | 1366x768     |    4 | yes  |
+| High@L4         | 1920x1080    |    6 | Yes  |
+| High@L4.1       | 1920x1080    |    6 | Yes  |
+| High@5          | 1920x1080    |    4 | No   |
+| High@5          | 1920x1080    |    6 | No   |
 =====  Two pass encoding =====
-Here it is a recipe of **two-pass encoding** from an high quality //master// produced with Olive Video Editor. The target video will be a 6 Mbit stream, 1920x1080@30. The profile level selected is High@L4.1, so that the video will play nicely with Kodi 19.4 on the Raspberry Pi 4:
+Here it is a recipe of **two-pass encoding** from an high quality //master// produced with [[olive_editor_tools#export_media|Olive Video Editor]]. The target video will be a **6 Mbit** stream, **1920x1080@30**. The profile level selected is **High@L4.1**, so that the video will play nicely with Kodi 19.4 on the Raspberry Pi 4:
 <code bash>
@@ Line 58: / Line 71: @@
     -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 \
@@ Line 71: / Line 84: @@
 </code>
-The transcoding works on the video only, suppressing any audio stream (**%%-an%%** option). Using the **keyint=64** option will produce a keyframe every 64 frame (about every two seconds), this make seeking back and forward in the video more smooth.
+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.
-=====  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  ^ Resolution   ^ Mbps  ^ Can play on Kodi  ^
-| High@L5         | 1366x768     |    4 | yes  |
-| High@L4         | 1920x1080    |    6 | Yes  |
-| High@L4.1       | 1920x1080    |    6 | Yes  |
-| High@5          | 1920x1080    |    4 | No   |
-| High@5          | 1920x1080    |    6 | No   |
 =====  Pixel format considerations =====