Changes between Version 39 and Version 40 of Encode/AAC

Timestamp:

Dec 5, 2015, 4:51:05 PM (11 years ago)

Author:

Rostislav Pehlivanov

Comment:

--

Encode/AAC

@@ -11 +11 @@
 ----
 
+== Native FFmpeg AAC encoder ==
+
+The native FFmpeg AAC encoder. This is currently the highest-quality AAC encoder available in FFmpeg and does not require an external library like the other AAC encoders described here. Results are usually as good or better than libfdk_aac at 128kbps but will occasionally sound worse below 96kbps. This is the default AAC encoder. The only drawback is that this encoder does not support the AAC-HE profile yet.
+
+==== Example using `-b:a` ====
+
+{{{
+ffmpeg -i input.wav -b:a 160k output.m4a
+}}}
+
+  '''Note:''' `-strict experimental` was previously required for this encoder, but is unneeded since December 2015.
+
+
+==== Example using `-q:a` ====
+
+{{{
+ffmpeg -i input.wav -strict experimental -c:a aac -q:a 3 output.m4a
+}}}
+
+Effective range for `-q:a` is around 0.1-10. This VBR is experimental and likely to get even worse results than the CBR.
+
+
+----
+
 == libfdk_aac ==#fdk_aac
 
-The Fraunhofer FDK AAC codec library. This is currently the highest-quality AAC encoder available with ffmpeg. Requires ffmpeg to be configured with `--enable-libfdk-aac` (and additionally `--enable-nonfree` if you're also using `--enable-gpl`). But beware, it defaults to a low-pass filter of around 14kHz ([[http://wiki.hydrogenaud.io/index.php?title=Fraunhofer_FDK_AAC#Bandwidth|details]]). If you want to preserve higher frequencies, use `-cutoff 18000`.  Adjust the number to the upper frequency limit you prefer. 
+The Fraunhofer FDK AAC codec library. Requires ffmpeg to be configured with `--enable-libfdk-aac` (and additionally `--enable-nonfree` if you're also using `--enable-gpl`). But beware, it defaults to a low-pass filter of around 14kHz ([[http://wiki.hydrogenaud.io/index.php?title=Fraunhofer_FDK_AAC#Bandwidth|details]]). If you want to preserve higher frequencies, use `-cutoff 18000`.  Adjust the number to the upper frequency limit you prefer. 
 
 Detailed information about the FDK AAC library (not FFmpeg specific) can be found at the [[http://wiki.hydrogenaud.io/index.php?title=Fraunhofer_FDK_AAC|Fraunhofer FDK AAC]] page in the HydrogenAudio Knowledgebase.
@@ -121 +145 @@
 ----
 
-== Native FFmpeg AAC encoder ==
-
-The native FFmpeg AAC encoder is included with ffmpeg and is does not require an external library like the other AAC encoders described here. Note that you will not get as good results as with `libfdk_aac`. This is considered an experimental encoder, so `-strict experimental` or `-strict -2` is required.
-
-==== Example using `-b:a` ====
-
-{{{
-ffmpeg -i input.wav -strict experimental -c:a aac -b:a 240k output.m4a
-}}}
-
-  '''Note:''' `-cutoff 15000` was previously recommended for this encoder, but this is now automatically applied since 2012 July.
-
-
-==== Example using `-q:a` ====
-
-{{{
-ffmpeg -i input.wav -strict experimental -c:a aac -q:a 6 output.m4a
-}}}
-
-Effective range for `-q:a` is around 0.1-10. This VBR is experimental and likely to get even worse results than the CBR. If ffmpeg ignores `-q:a` then get a newer build (see ticket #[ticket:1346]).
-
-
-----
-
 == libvo_aacenc ==
 
@@ -187 +187 @@
 === Which encoder should I use? What provides the best quality? ===
 
-For AAC-LC the likely answer is: `libfdk_aac` > `libfaac` > Native FFmpeg AAC encoder (`aac`) > `libvo_aacenc`.
+For AAC-LC the likely answer is: Native FFmpeg AAC encoder (`aac`) >= `libfdk_aac` > `libfaac` > `libvo_aacenc`.
 
 === Should I use AAC-LC or AAC-HE? ===
 
 If you require a low audio bitrate, such as ≤ 32kbs/channel, then AAC-HE would be worth considering if your player or device can support AAC-HE decoding. Anything higher may benefit more from AAC-LC due to less processing. If in doubt use AAC-LC. All players supporting AAC-HE also support AAC-LC.
-
-=== I get an error about "experimental codecs". What does this mean? ===
-
-Some encoders, such as the native FFmpeg AAC encoder (`aac`), are considered experimental and require the addition of `-strict experimental` or `-strict -2` (same thing, different name) to your command as an output option. Otherwise you may see:
-
-{{{
-The encoder 'aac' is experimental but experimental codecs are not enabled, add '-strict -2' if you want to use it.
-}}}
-
-So, for example, given a command line such as:
-
-{{{
-ffmpeg -i file.avi file.mov
-}}}
-
-you may need to invoke `ffmpeg` as follows for the experimental codec to be enabled:
-
-{{{
-ffmpeg -i file.avi -strict -2 file.mov
-}}}
-
-----
 
 == Also See ==