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--- ubuntu:video:encoding_h.265_hevc_with_ffmpeg [2019/12/10 22:08] – peter
+++ ubuntu:video:encoding_h.265_hevc_with_ffmpeg [2023/06/11 21:45] (current) – [Audio and Dolby Digital Plus] peter
@@ Line 4: / Line 4: @@
 <code bash>
-ffmpeg -c:v libx265 -preset fast -crf 28 -tag:v hvc1 -c:a eac3 -b:a 224k -i <source> <target>
+ffmpeg -c:v libx265 -preset fast -crf 28 -c:a aac -ac 2 -b:a 224k -i <source> <target>
 </code>
@@ Line 10: / Line 10: @@
 <code bash>
-ffmpeg -vcodec hevc_videotoolbox -b:v 6000k -tag:v hvc1 -c:a eac3 -b:a 224k -i <source> <target>
+ffmpeg -vcodec hevc_videotoolbox -b:v 6000k -c:a aac -ac 2 -b:a 224k -i <source> <target>
 </code>
+crf 28 in H265 is the equivalent of crf 23 in H264.
 ----
@@ Line 24: / Line 25: @@
 The right compromise is to use libx265 for any videos that you want to keep around, but for videos that you’d prefer encoded quickly and will probably delete (say you want them for a single trip), hevc_videotoolbox is perfectly fine.  Output videos are still small enough, and the significantly faster encoding speeds mean that FFmpeg finishes far more quickly.
+If you’re going for quality/size, make sure you don’t enable any hardware acceleration.
 ----
@@ Line 29: / Line 32: @@
 ===== Audio and Dolby Digital Plus =====
-**-c:a eac3** tells FFmpeg to re-encode video using Dolby Digital Plus.  You might wonder why I would ever choose that over AAC, and the answer is simple: Apple.
+Have FFmpeg downmix to stereo AAC.
-Dolby Digital Plus is strictly worse than AAC, so you should prefer the latter in most situations.  However, if you’re encoding video for QuickTime (or any Apple target), you have to consider that thanks to the company’s [[https://developer.apple.com/documentation/http_live_streaming/hls_authoring_specification_for_apple_devices|opaque quirks]], their devices support AAC in stereo only.  They support multi-channel audio, but only if it uses a “blessed” multi-channel codec like Dolby Digital Plus 1.
-You might want to change this parameter if (1) your input sources are just stereo anyway, or (2) you never expect to watch the output video on anything but a stereo device (i.e., headphones, TV minus sound system). It’s trivial to have FFmpeg downmix to stereo AAC instead:
 <code bash>
@@ Line 49: / Line 48: @@
 ----
-===== The `hvc1` tag =====
+===== Check =====
-The argument **-tag:v hvc1** tags the video with hvc1, which is purely for QuickTime’s benefit.  It allows this Very Stupid Player to recognize the fact that it will be able to play the resulting file.
+To check to see that the file has been encoded correctly, use the **ffprobe** command like this:
-<WRAP info>
+<code bash>
-Why QuickTime won’t open the encoded files: It isn’t the video Apple didn’t like, it is the 5.1 AAC.
+ffprobe video-h265.mp4
-</WRAP>
+</code>
+The output will show that the video stream (probably stream#0) is encoded using hvec, i.e. H.265.
+----
 ===== References =====
@@ Line 62: / Line 64: @@
 https://trac.ffmpeg.org/wiki/Encode/H.265
-https://developer.apple.com/documentation/http_live_streaming/hls_authoring_specification_for_apple_devices