Does ffmpeg's aac encoder need a audio bitrate?
up vote
2
down vote
favorite
What happens if you do not set a audio bitrate in the aac encoder ?
-ab 128k
Does it automaticly select the highest bitrate it can or something i am curious if i should do this or if it will be bad i see no difference.
ffmpeg aac
asked Jan 1 '15 at 11:30
C0nw0nk
184311
add a comment |
up vote
2
down vote
favorite
What happens if you do not set a audio bitrate in the aac encoder ?
-ab 128k
Does it automaticly select the highest bitrate it can or something i am curious if i should do this or if it will be bad i see no difference.
ffmpeg aac
asked Jan 1 '15 at 11:30
C0nw0nk
184311
Why would you not try it? And then for the output file doffmpeg -i outputfile. It will tell you what bitrate the audio is at. No encoderdetectsincoming bitrate it justs falls to defaults.
– Rajib
Jan 1 '15 at 14:25
add a comment |
up vote
2
down vote
favorite
up vote
2
down vote
favorite
What happens if you do not set a audio bitrate in the aac encoder ?
-ab 128k
Does it automaticly select the highest bitrate it can or something i am curious if i should do this or if it will be bad i see no difference.
ffmpeg aac
asked Jan 1 '15 at 11:30
C0nw0nk
184311
What happens if you do not set a audio bitrate in the aac encoder ?
-ab 128k
Does it automaticly select the highest bitrate it can or something i am curious if i should do this or if it will be bad i see no difference.
ffmpeg aac
ffmpeg aac
asked Jan 1 '15 at 11:30
C0nw0nk
184311
asked Jan 1 '15 at 11:30
C0nw0nk
184311
asked Jan 1 '15 at 11:30
C0nw0nk
184311
asked Jan 1 '15 at 11:30
C0nw0nk
184311
asked Jan 1 '15 at 11:30
C0nw0nk
184311
184311
Why would you not try it? And then for the output file doffmpeg -i outputfile. It will tell you what bitrate the audio is at. No encoderdetectsincoming bitrate it justs falls to defaults.
– Rajib
Jan 1 '15 at 14:25
add a comment |
Why would you not try it? And then for the output file doffmpeg -i outputfile. It will tell you what bitrate the audio is at. No encoderdetectsincoming bitrate it justs falls to defaults.
– Rajib
Jan 1 '15 at 14:25
Why would you not try it? And then for the output file do
ffmpeg -i outputfile. It will tell you what bitrate the audio is at. No encoder detects incoming bitrate it justs falls to defaults.– Rajib
Jan 1 '15 at 14:25
Why would you not try it? And then for the output file do
ffmpeg -i outputfile. It will tell you what bitrate the audio is at. No encoder detects incoming bitrate it justs falls to defaults.– Rajib
Jan 1 '15 at 14:25
add a comment |
2 Answers
2
active
oldest
votes
up vote
5
down vote
accepted
It totally depends on the AAC encoder you are using. ffmpeg can use several AAC encoders:
aac(ffmpeg-internal) – defaults to 128 kBit/s for both mono and stereo.
libfdk-aac– defaults to 128 kBit/s for stereo and 96 kBit/s CBR for mono.
In general, you should choose a higher bitrate than the default for aac. This is because it produces somewhat lower quality than libfdk-aac at the same bitrate. Do that by setting -b:a appropriately, e.g. -b:a 192k.
I tried to summarize the VBR options on my homepage, and the FFmpeg Wiki has good info on AAC encoding as well as some example commands.
Also, when you see a line similar to this in ffmpeg's log output:
Stream #0:0: Audio: aac (libfdk_aac) (mp4a / 0x6134706D), … 96 kb/s
Then the kb/s shown here do not necessarily reflect what the encoder will really use, as it's up to the specific implementation.
There are also some encoders that are not supported anymore by ffmpeg:
libfaac– defaults to VBR setting of 100, which results in about 128 kBit/s for stereo audio (reference).
libvo-aacenc– defaults to 128 kBit/s for both mono and stereo.libaacplus
answered Jan 1 '15 at 15:44
slhck
158k47437461
Thanks so what is the recommended bitrate i should use with aac before i had it set to -ab 192k and i kept getting bit_rate width height error what is kind of annoying.
– C0nw0nk
Jan 1 '15 at 15:49
1
The recommended bitrate depends on what your application is, and what encoder you are using. For web video, you probably want 128 kBit/s but not much more. For listening to music, I'd go higher than that. For the internal AAC encoder, 192 kBit/s is very good quality. I don't know what a "bit_rate width height error" is, though. If that is your real problem, then you should ask a new question about the error and show the complete, uncut command line output from ffmpeg.
– slhck
Jan 1 '15 at 16:01
Unless it's this question you already asked: superuser.com/questions/805196/… — you got a good answer there already.
– slhck
Jan 1 '15 at 16:02
Thanks i set it to be -ab 128k and i will just wait and see if that error ever comes back.
– C0nw0nk
Jan 1 '15 at 16:26
add a comment |
up vote
-1
down vote
Libfaac sets a default bitrate. 128k for a stereo input and 96k for mono.
answered Jan 1 '15 at 13:53
stib
2,30341930
The OP is talking about "ffmpeg's aac encoder", not FAAC.
– slhck
Jan 1 '15 at 15:29
True. But if I don't specify an encoder libFAAC is the default. Maybe it's just the way my build of ffmpeg works.
– stib
Jan 2 '15 at 11:01
Yeah, that's assuming ffmpeg is built with libfaac. In the default configuration, it will fail to convert to AAC, since the internal AAC encoder needs the-strict experimentalflag.
– slhck
Jan 2 '15 at 11:06
add a comment |
2 Answers
2
active
oldest
votes
2 Answers
2
active
oldest
votes
active
oldest
votes
active
oldest
votes
up vote
5
down vote
accepted
It totally depends on the AAC encoder you are using. ffmpeg can use several AAC encoders:
aac(ffmpeg-internal) – defaults to 128 kBit/s for both mono and stereo.
libfdk-aac– defaults to 128 kBit/s for stereo and 96 kBit/s CBR for mono.
In general, you should choose a higher bitrate than the default for aac. This is because it produces somewhat lower quality than libfdk-aac at the same bitrate. Do that by setting -b:a appropriately, e.g. -b:a 192k.
I tried to summarize the VBR options on my homepage, and the FFmpeg Wiki has good info on AAC encoding as well as some example commands.
Also, when you see a line similar to this in ffmpeg's log output:
Stream #0:0: Audio: aac (libfdk_aac) (mp4a / 0x6134706D), … 96 kb/s
Then the kb/s shown here do not necessarily reflect what the encoder will really use, as it's up to the specific implementation.
There are also some encoders that are not supported anymore by ffmpeg:
libfaac– defaults to VBR setting of 100, which results in about 128 kBit/s for stereo audio (reference).
libvo-aacenc– defaults to 128 kBit/s for both mono and stereo.libaacplus
answered Jan 1 '15 at 15:44
slhck
158k47437461
Thanks so what is the recommended bitrate i should use with aac before i had it set to -ab 192k and i kept getting bit_rate width height error what is kind of annoying.
– C0nw0nk
Jan 1 '15 at 15:49
1
The recommended bitrate depends on what your application is, and what encoder you are using. For web video, you probably want 128 kBit/s but not much more. For listening to music, I'd go higher than that. For the internal AAC encoder, 192 kBit/s is very good quality. I don't know what a "bit_rate width height error" is, though. If that is your real problem, then you should ask a new question about the error and show the complete, uncut command line output from ffmpeg.
– slhck
Jan 1 '15 at 16:01
Unless it's this question you already asked: superuser.com/questions/805196/… — you got a good answer there already.
– slhck
Jan 1 '15 at 16:02
Thanks i set it to be -ab 128k and i will just wait and see if that error ever comes back.
– C0nw0nk
Jan 1 '15 at 16:26
add a comment |
up vote
5
down vote
accepted
It totally depends on the AAC encoder you are using. ffmpeg can use several AAC encoders:
aac(ffmpeg-internal) – defaults to 128 kBit/s for both mono and stereo.
libfdk-aac– defaults to 128 kBit/s for stereo and 96 kBit/s CBR for mono.
In general, you should choose a higher bitrate than the default for aac. This is because it produces somewhat lower quality than libfdk-aac at the same bitrate. Do that by setting -b:a appropriately, e.g. -b:a 192k.
I tried to summarize the VBR options on my homepage, and the FFmpeg Wiki has good info on AAC encoding as well as some example commands.
Also, when you see a line similar to this in ffmpeg's log output:
Stream #0:0: Audio: aac (libfdk_aac) (mp4a / 0x6134706D), … 96 kb/s
Then the kb/s shown here do not necessarily reflect what the encoder will really use, as it's up to the specific implementation.
There are also some encoders that are not supported anymore by ffmpeg:
libfaac– defaults to VBR setting of 100, which results in about 128 kBit/s for stereo audio (reference).
libvo-aacenc– defaults to 128 kBit/s for both mono and stereo.libaacplus
answered Jan 1 '15 at 15:44
slhck
158k47437461
Thanks so what is the recommended bitrate i should use with aac before i had it set to -ab 192k and i kept getting bit_rate width height error what is kind of annoying.
– C0nw0nk
Jan 1 '15 at 15:49
1
The recommended bitrate depends on what your application is, and what encoder you are using. For web video, you probably want 128 kBit/s but not much more. For listening to music, I'd go higher than that. For the internal AAC encoder, 192 kBit/s is very good quality. I don't know what a "bit_rate width height error" is, though. If that is your real problem, then you should ask a new question about the error and show the complete, uncut command line output from ffmpeg.
– slhck
Jan 1 '15 at 16:01
Unless it's this question you already asked: superuser.com/questions/805196/… — you got a good answer there already.
– slhck
Jan 1 '15 at 16:02
Thanks i set it to be -ab 128k and i will just wait and see if that error ever comes back.
– C0nw0nk
Jan 1 '15 at 16:26
add a comment |
up vote
5
down vote
accepted
up vote
5
down vote
accepted
It totally depends on the AAC encoder you are using. ffmpeg can use several AAC encoders:
aac(ffmpeg-internal) – defaults to 128 kBit/s for both mono and stereo.
libfdk-aac– defaults to 128 kBit/s for stereo and 96 kBit/s CBR for mono.
In general, you should choose a higher bitrate than the default for aac. This is because it produces somewhat lower quality than libfdk-aac at the same bitrate. Do that by setting -b:a appropriately, e.g. -b:a 192k.
I tried to summarize the VBR options on my homepage, and the FFmpeg Wiki has good info on AAC encoding as well as some example commands.
Also, when you see a line similar to this in ffmpeg's log output:
Stream #0:0: Audio: aac (libfdk_aac) (mp4a / 0x6134706D), … 96 kb/s
Then the kb/s shown here do not necessarily reflect what the encoder will really use, as it's up to the specific implementation.
There are also some encoders that are not supported anymore by ffmpeg:
libfaac– defaults to VBR setting of 100, which results in about 128 kBit/s for stereo audio (reference).
libvo-aacenc– defaults to 128 kBit/s for both mono and stereo.libaacplus
answered Jan 1 '15 at 15:44
slhck
158k47437461
It totally depends on the AAC encoder you are using. ffmpeg can use several AAC encoders:
aac(ffmpeg-internal) – defaults to 128 kBit/s for both mono and stereo.
libfdk-aac– defaults to 128 kBit/s for stereo and 96 kBit/s CBR for mono.
In general, you should choose a higher bitrate than the default for aac. This is because it produces somewhat lower quality than libfdk-aac at the same bitrate. Do that by setting -b:a appropriately, e.g. -b:a 192k.
I tried to summarize the VBR options on my homepage, and the FFmpeg Wiki has good info on AAC encoding as well as some example commands.
Also, when you see a line similar to this in ffmpeg's log output:
Stream #0:0: Audio: aac (libfdk_aac) (mp4a / 0x6134706D), … 96 kb/s
Then the kb/s shown here do not necessarily reflect what the encoder will really use, as it's up to the specific implementation.
There are also some encoders that are not supported anymore by ffmpeg:
libfaac– defaults to VBR setting of 100, which results in about 128 kBit/s for stereo audio (reference).
libvo-aacenc– defaults to 128 kBit/s for both mono and stereo.libaacplus
answered Jan 1 '15 at 15:44
slhck
158k47437461
edited Nov 22 at 9:45
answered Jan 1 '15 at 15:44
slhck
158k47437461
answered Jan 1 '15 at 15:44
slhck
158k47437461
answered Jan 1 '15 at 15:44
slhck
158k47437461
158k47437461
Thanks so what is the recommended bitrate i should use with aac before i had it set to -ab 192k and i kept getting bit_rate width height error what is kind of annoying.
– C0nw0nk
Jan 1 '15 at 15:49
1
The recommended bitrate depends on what your application is, and what encoder you are using. For web video, you probably want 128 kBit/s but not much more. For listening to music, I'd go higher than that. For the internal AAC encoder, 192 kBit/s is very good quality. I don't know what a "bit_rate width height error" is, though. If that is your real problem, then you should ask a new question about the error and show the complete, uncut command line output from ffmpeg.
– slhck
Jan 1 '15 at 16:01
Unless it's this question you already asked: superuser.com/questions/805196/… — you got a good answer there already.
– slhck
Jan 1 '15 at 16:02
Thanks i set it to be -ab 128k and i will just wait and see if that error ever comes back.
– C0nw0nk
Jan 1 '15 at 16:26
add a comment |
Thanks so what is the recommended bitrate i should use with aac before i had it set to -ab 192k and i kept getting bit_rate width height error what is kind of annoying.
– C0nw0nk
Jan 1 '15 at 15:49
1
The recommended bitrate depends on what your application is, and what encoder you are using. For web video, you probably want 128 kBit/s but not much more. For listening to music, I'd go higher than that. For the internal AAC encoder, 192 kBit/s is very good quality. I don't know what a "bit_rate width height error" is, though. If that is your real problem, then you should ask a new question about the error and show the complete, uncut command line output from ffmpeg.
– slhck
Jan 1 '15 at 16:01
Unless it's this question you already asked: superuser.com/questions/805196/… — you got a good answer there already.
– slhck
Jan 1 '15 at 16:02
Thanks i set it to be -ab 128k and i will just wait and see if that error ever comes back.
– C0nw0nk
Jan 1 '15 at 16:26
Thanks so what is the recommended bitrate i should use with aac before i had it set to -ab 192k and i kept getting bit_rate width height error what is kind of annoying.
– C0nw0nk
Jan 1 '15 at 15:49
Thanks so what is the recommended bitrate i should use with aac before i had it set to -ab 192k and i kept getting bit_rate width height error what is kind of annoying.
– C0nw0nk
Jan 1 '15 at 15:49
1
1
The recommended bitrate depends on what your application is, and what encoder you are using. For web video, you probably want 128 kBit/s but not much more. For listening to music, I'd go higher than that. For the internal AAC encoder, 192 kBit/s is very good quality. I don't know what a "bit_rate width height error" is, though. If that is your real problem, then you should ask a new question about the error and show the complete, uncut command line output from ffmpeg.
– slhck
Jan 1 '15 at 16:01
The recommended bitrate depends on what your application is, and what encoder you are using. For web video, you probably want 128 kBit/s but not much more. For listening to music, I'd go higher than that. For the internal AAC encoder, 192 kBit/s is very good quality. I don't know what a "bit_rate width height error" is, though. If that is your real problem, then you should ask a new question about the error and show the complete, uncut command line output from ffmpeg.
– slhck
Jan 1 '15 at 16:01
Unless it's this question you already asked: superuser.com/questions/805196/… — you got a good answer there already.
– slhck
Jan 1 '15 at 16:02
Unless it's this question you already asked: superuser.com/questions/805196/… — you got a good answer there already.
– slhck
Jan 1 '15 at 16:02
Thanks i set it to be -ab 128k and i will just wait and see if that error ever comes back.
– C0nw0nk
Jan 1 '15 at 16:26
Thanks i set it to be -ab 128k and i will just wait and see if that error ever comes back.
– C0nw0nk
Jan 1 '15 at 16:26
add a comment |
up vote
-1
down vote
Libfaac sets a default bitrate. 128k for a stereo input and 96k for mono.
answered Jan 1 '15 at 13:53
stib
2,30341930
The OP is talking about "ffmpeg's aac encoder", not FAAC.
– slhck
Jan 1 '15 at 15:29
True. But if I don't specify an encoder libFAAC is the default. Maybe it's just the way my build of ffmpeg works.
– stib
Jan 2 '15 at 11:01
Yeah, that's assuming ffmpeg is built with libfaac. In the default configuration, it will fail to convert to AAC, since the internal AAC encoder needs the-strict experimentalflag.
– slhck
Jan 2 '15 at 11:06
add a comment |
up vote
-1
down vote
Libfaac sets a default bitrate. 128k for a stereo input and 96k for mono.
answered Jan 1 '15 at 13:53
stib
2,30341930
The OP is talking about "ffmpeg's aac encoder", not FAAC.
– slhck
Jan 1 '15 at 15:29
True. But if I don't specify an encoder libFAAC is the default. Maybe it's just the way my build of ffmpeg works.
– stib
Jan 2 '15 at 11:01
Yeah, that's assuming ffmpeg is built with libfaac. In the default configuration, it will fail to convert to AAC, since the internal AAC encoder needs the-strict experimentalflag.
– slhck
Jan 2 '15 at 11:06
add a comment |
up vote
-1
down vote
up vote
-1
down vote
Libfaac sets a default bitrate. 128k for a stereo input and 96k for mono.
answered Jan 1 '15 at 13:53
stib
2,30341930
Libfaac sets a default bitrate. 128k for a stereo input and 96k for mono.
answered Jan 1 '15 at 13:53
stib
2,30341930
answered Jan 1 '15 at 13:53
stib
2,30341930
answered Jan 1 '15 at 13:53
stib
2,30341930
answered Jan 1 '15 at 13:53
stib
2,30341930
2,30341930
The OP is talking about "ffmpeg's aac encoder", not FAAC.
– slhck
Jan 1 '15 at 15:29
True. But if I don't specify an encoder libFAAC is the default. Maybe it's just the way my build of ffmpeg works.
– stib
Jan 2 '15 at 11:01
Yeah, that's assuming ffmpeg is built with libfaac. In the default configuration, it will fail to convert to AAC, since the internal AAC encoder needs the-strict experimentalflag.
– slhck
Jan 2 '15 at 11:06
add a comment |
The OP is talking about "ffmpeg's aac encoder", not FAAC.
– slhck
Jan 1 '15 at 15:29
True. But if I don't specify an encoder libFAAC is the default. Maybe it's just the way my build of ffmpeg works.
– stib
Jan 2 '15 at 11:01
Yeah, that's assuming ffmpeg is built with libfaac. In the default configuration, it will fail to convert to AAC, since the internal AAC encoder needs the-strict experimentalflag.
– slhck
Jan 2 '15 at 11:06
The OP is talking about "ffmpeg's aac encoder", not FAAC.
– slhck
Jan 1 '15 at 15:29
The OP is talking about "ffmpeg's aac encoder", not FAAC.
– slhck
Jan 1 '15 at 15:29
True. But if I don't specify an encoder libFAAC is the default. Maybe it's just the way my build of ffmpeg works.
– stib
Jan 2 '15 at 11:01
True. But if I don't specify an encoder libFAAC is the default. Maybe it's just the way my build of ffmpeg works.
– stib
Jan 2 '15 at 11:01
Yeah, that's assuming ffmpeg is built with libfaac. In the default configuration, it will fail to convert to AAC, since the internal AAC encoder needs the
-strict experimental flag.– slhck
Jan 2 '15 at 11:06
Yeah, that's assuming ffmpeg is built with libfaac. In the default configuration, it will fail to convert to AAC, since the internal AAC encoder needs the
-strict experimental flag.– slhck
Jan 2 '15 at 11:06
add a comment |
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Why would you not try it? And then for the output file do
ffmpeg -i outputfile. It will tell you what bitrate the audio is at. No encoderdetectsincoming bitrate it justs falls to defaults.– Rajib
Jan 1 '15 at 14:25