Command line to show channel label/position
Hello there, What is the best command line to get details about channels position/label in a multichannel audio file ? I tried ffprobe but I get only channels=6 channel_layout=5.1 not FR, FL, C, LFE, BL ... BTW what is the best way to name this parameter ? *ffprobe -show_streams -i 102MJ.flac* ffprobe version 4.4.4 Copyright (c) 2007-2023 the FFmpeg developers built with gcc 7 (SUSE Linux) configuration: --prefix=/usr --libdir=/usr/lib64 --shlibdir=/usr/lib64 --incdir=/usr/include/ffmpeg --extra-cflags='-fmessage-length=0 -grecord-gcc-switches -O2 -Wall -D_FORTIFY_SOURCE=2 -fstack-protector-strong -funwind-tables -fasynchronous-unwind-tables -fstack-clash-protection -g' --optflags='-fmessage-length=0 -grecord-gcc-switches -O2 -Wall -D_FORTIFY_SOURCE=2 -fstack-protector-strong -funwind-tables -fasynchronous-unwind-tables -fstack-clash-protection -g' --disable-htmlpages --enable-pic --disable-stripping --enable-shared --disable-static --enable-gpl --enable-version3 --enable-libsmbclient --disable-openssl --enable-avresample --enable-gnutls --enable-ladspa --enable-libass --enable-libbluray --enable-libbs2b --enable-libcelt --enable-libcdio --enable-libdav1d --enable-libdc1394 --enable-libdrm --enable-libfontconfig --enable-libfreetype --enable-libfribidi --enable-libgsm --enable-libjack --enable-libmp3lame --enable-libopenjpeg --enable-libopenmpt --enable-libopus --enable-libpulse --enable-libspeex --enable-libssh --enable-libtheora --enable-libtwolame --enable-libvidstab --enable-libvorbis --enable-libv4l2 --enable-libvpx --enable-libwebp --enable-libxml2 --enable-libzimg --enable-libzvbi --enable-vaapi --enable-vdpau --enable-version3 --enable-libfdk-aac-dlopen --enable-nonfree --enable-libvo-amrwbenc --enable-libx264 --enable-libx265 --enable-librtmp --enable-libxvid libavutil 56. 70.100 / 56. 70.100 libavcodec 58.134.100 / 58.134.100 libavformat 58. 76.100 / 58. 76.100 libavdevice 58. 13.100 / 58. 13.100 libavfilter 7.110.100 / 7.110.100 libavresample 4. 0. 0 / 4. 0. 0 libswscale 5. 9.100 / 5. 9.100 libswresample 3. 9.100 / 3. 9.100 libpostproc 55. 9.100 / 55. 9.100 Input #0, flac, from '102MJ.flac': Metadata: encoder : Lavf58.76.100 Duration: 00:03:01.31, start: 0.000000, bitrate: 1388 kb/s Stream #0:0: Audio: flac, 44100 Hz, 5.1, s16 [STREAM] index=0 codec_name=flac codec_long_name=FLAC (Free Lossless Audio Codec) profile=unknown codec_type=audio codec_tag_string=[0][0][0][0] codec_tag=0x0000 sample_fmt=s16 sample_rate=44100 *channels=6 channel_layout=5.1* bits_per_sample=0 id=N/A r_frame_rate=0/0 avg_frame_rate=0/0 time_base=1/44100 start_pts=0 start_time=0.000000 duration_ts=7995624 duration=181.306667 bit_rate=N/A max_bit_rate=N/A bits_per_raw_sample=16 nb_frames=N/A nb_read_frames=N/A nb_read_packets=N/A DISPOSITION:default=0 DISPOSITION:dub=0 DISPOSITION:original=0 DISPOSITION:comment=0 DISPOSITION:lyrics=0 DISPOSITION:karaoke=0 DISPOSITION:forced=0 DISPOSITION:hearing_impaired=0 DISPOSITION:visual_impaired=0 DISPOSITION:clean_effects=0 DISPOSITION:attached_pic=0 DISPOSITION:timed_thumbnails=0 [/STREAM] Thanks
On Jan 26, 2025, at 11:24 AM, MrNice <wxcvbn2006@iol.ie> wrote:
Hello there,
What is the best command line to get details about channels position/label in a multichannel audio file ?
I think that rather than using ffmpeg for this, the "mediainfo" executable might provide an easier way. Once I have "mediainfo" correctly installed for my system, I can simply run the command, "mediainfo mymediafile", and see this list of audio channels and their disposition among the results for a movie file containing a 5.1 audio stream: Channel layout : L R C LFE Ls Rs More descriptive labels for those might be (relatively): front left, front right, front center, low frequency effect, side left, side right (in case that is helpful). The output of "mediainfo" that you would need to examine would likely be much shorter if you pointed it toward an audio file. And there are lots of ways to limit that output, although I haven't explored that too much. You can use ffmpeg to manipulate the output as illustrated here (if it helps): https://trac.ffmpeg.org/wiki/AudioChannelManipulation#a5.1stereo L. Lee
On Jan 26, 2025, at 11:24 AM, MrNice <wxcvbn2006@iol.ie> wrote:
Hello there,
What is the best command line to get details about channels position/label in a multichannel audio file ?
I think that rather than using ffmpeg for this, the "mediainfo" executable might provide an easier way. Once I have "mediainfo" correctly installed for my system, I can simply run the command, "mediainfo mymediafile", and see this list of audio channels and their disposition among the results for a movie file containing a 5.1 audio stream:
Channel layout : L R C LFE Ls Rs
More descriptive labels for those might be (relatively): front left, front right, front center, low frequency effect, side left, side right (in case that is helpful).
The output of "mediainfo" that you would need to examine would likely be much shorter if you pointed it toward an audio file. And there are lots of ways to limit that output, although I haven't explored that too much.
You can use ffmpeg to manipulate the output as illustrated here (if it helps): https://trac.ffmpeg.org/wiki/AudioChannelManipulation#a5.1stereo
L. Lee _______________________________________________ ffmpeg-user mailing list ffmpeg-user@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-user
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Thank you L. I'll use Mediainfo, I have it installed but I thought ffprobe has a command for that. BTW, could you tell me, How the decoder will sort out the channels to send to the right speaker ? - by the list order, I mean first to FL, second to FR, and so on - or by the label, and what happen when there is no label or multi mono channels ?
On Jan 27, 2025, at 6:28 AM, MrNice <wxcvbn2006@iol.ie> wrote:
Thank you L. I'll use Mediainfo, I have it installed but I thought ffprobe has a command for that.
BTW, could you tell me, How the decoder will sort out the channels to send to the right speaker ? - by the list order, I mean first to FL, second to FR, and so on - or by the label, and what happen when there is no label or multi mono channels ?
I’m not sure I have an answer for that, but maybe you can use the disposition resource page I linked to run some of your own experiments. For example, make your own stereo recording of a statement such as “this is the left channel” with the right mic turned off. Then use the disposition instructions to move and/or copy it to the channel of your choice, then audition the results. If you want, and have the necessary equipment, you should be able to reassign any existing audio channel to any other. L. Lee
Thank you L. I'll use Mediainfo, I have it installed but I thought ffprobe has a command for that.
BTW, could you tell me, How the decoder will sort out the channels to send to the right speaker ? - by the list order, I mean first to FL, second to FR, and so on - or by the label, and what happen when there is no label or multi mono channels ?
I’m not sure I have an answer for that, but maybe you can use the disposition resource page I linked to run some of your own experiments. For example, make your own stereo recording of a statement such as “this is the left channel” with the right mic turned off. Then use the disposition instructions to move and/or copy it to the channel of your choice, then audition the results. If you want, and have the necessary equipment, you should be able to reassign any existing audio channel to any other. L. Lee _______________________________________________ I came accross this command. Is it reliable? ffprobe -v error -show_entries stream=channel_layout -of csv=p=0 filename.flac ffmpeg -v error -layouts | awk '/5.1 /{print $2}' Thanks
Thank you L. I'll use Mediainfo, I have it installed but I thought ffprobe has a command for that.
BTW, could you tell me, How the decoder will sort out the channels to send to the right speaker ? - by the list order, I mean first to FL, second to FR, and so on - or by the label, and what happen when there is no label or multi mono channels ?
I’m not sure I have an answer for that, but maybe you can use the disposition resource page I linked to run some of your own experiments. For example, make your own stereo recording of a statement such as “this is the left channel” with the right mic turned off. Then use the disposition instructions to move and/or copy it to the channel of your choice, then audition the results. If you want, and have the necessary equipment, you should be able to reassign any existing audio channel to any other.
L. Lee _______________________________________________
I came accross this command. Is it reliable?
ffprobe -v error -show_entries stream=channel_layout -of csv=p=0 filename.flac ffmpeg -v error -layouts | awk '/5.1 /{print $2}'
Thanks _______________________________________________
I have an audio file, with MediaInfo I get Audio Format : FLAC Format/Info : Free Lossless Audio Codec Duration : 2 min 18 s Bit rate mode : Variable Bit rate : 5 439 kb/s Channel(s) : 4 channels Channel layout : L R Ls Rs Sampling rate : 96.0 kHz Bit depth : 24 bits Compression mode : Lossless With the above ffprobe command, I get
ffprobe -v error -show_entries stream=channel_layout -of csv=p=0 101Be.flac quad ffmpeg -v error -layouts | awk '/quad /{print $2}' FL+FR+BL+BR
What is the correct answer?
On 1/28/2025 8:18 AM, MrNice wrote:
have an audio file, with MediaInfo I get Audio Channel layout : L R Ls Rs
ffmpeg -v error -layouts | awk '/quad /{print $2}' FL+FR+BL+BR
What is the correct answer?
Both. Left, assumed to be front (L) = Front Left (FL) Left surround/side (Ls) = Back Left (BL) etc (that's part way down the AudioChannelManipulation page, even farther down is a list of the channel names and standard layouts, also in the -layouts output) z!
On 28/01/2025 18:26, Carl Zwanzig wrote:
On 1/28/2025 8:18 AM, MrNice wrote:
have an audio file, with MediaInfo I get Audio Channel layout : L R Ls Rs
> ffmpeg -v error -layouts | awk '/quad /{print $2}' FL+FR+BL+BR
What is the correct answer?
Both. Left, assumed to be front (L) = Front Left (FL) Left surround/side (Ls) = Back Left (BL) etc
(that's part way down the AudioChannelManipulation page, even farther down is a list of the channel names and standard layouts, also in the -layouts output)
z!
_______________________________________________
Are you sure for good Carl? AFAIK, LS is surround and BL is back/Rear Please look here https://mediaarea.net/AudioChannelLayout They say, depending of standardization; Left Surround = Ls = CL = SL = Ls (MediaInfo name) Right Surround = Rs = CR = SR = Rs (MediaInfo name) Left Rear Surround = Lrs = BL = Lsr = SL = Lb (MediaInfo name) Right Rear Surround = Rrs = BR = Rsr = Rb (MediaInfo name)
On Jan 28, 2025, at 4:14 PM, MrNice <wxcvbn2006@iol.ie> wrote:
On 28/01/2025 18:26, Carl Zwanzig wrote:
On 1/28/2025 8:18 AM, MrNice wrote:
have an audio file, with MediaInfo I get Audio Channel layout : L R Ls Rs
ffmpeg -v error -layouts | awk '/quad /{print $2}' FL+FR+BL+BR
What is the correct answer?
Both. Left, assumed to be front (L) = Front Left (FL) Left surround/side (Ls) = Back Left (BL) etc
(that's part way down the AudioChannelManipulation page, even farther down is a list of the channel names and standard layouts, also in the -layouts output)
z!
_______________________________________________
Are you sure for good Carl?
AFAIK, LS is surround and BL is back/Rear
Please look here
https://mediaarea.net/AudioChannelLayout
They say, depending of standardization; Left Surround = Ls = CL = SL = Ls (MediaInfo name) Right Surround = Rs = CR = SR = Rs (MediaInfo name) Left Rear Surround = Lrs = BL = Lsr = SL = Lb (MediaInfo name) Right Rear Surround = Rrs = BR = Rsr = Rb (MediaInfo name)
I'm not sure I understand the question, but I believe that "back" channels are only involved if there are more than 5 distinct audio signals plus one low frequency signal. By way of explanation, I believe that 5 distinct audio signals plus one low frequency signal is the configuration commonly referred to as "5.1" audio (front left, front right, center, side left, side right, and low frequency). I don't believe that the term "5.1" when used to describe an audio standard (summarized as the description of speaker locations listed in my previous sentence) specifies any "back' audio signals at all. If you wish to convert 5.1 audio to an audio format having more distinct signals or sends, then I think it is up to you to determine how you would like to distribute the audio signals to make use of the additional available channels. Did I say anything useful, or have I just confused the issue? LL
On Jan 28, 2025, at 4:14 PM, MrNice <wxcvbn2006@iol.ie> wrote:
On 28/01/2025 18:26, Carl Zwanzig wrote:
On 1/28/2025 8:18 AM, MrNice wrote:
have an audio file, with MediaInfo I get Audio Channel layout : L R Ls Rs
ffmpeg -v error -layouts | awk '/quad /{print $2}' FL+FR+BL+BR What is the correct answer? Both. Left, assumed to be front (L) = Front Left (FL) Left surround/side (Ls) = Back Left (BL) etc
(that's part way down the AudioChannelManipulation page, even farther down is a list of the channel names and standard layouts, also in the -layouts output)
z!
_______________________________________________ Are you sure for good Carl?
AFAIK, LS is surround and BL is back/Rear
Please look here
https://mediaarea.net/AudioChannelLayout
They say, depending of standardization; Left Surround = Ls = CL = SL = Ls (MediaInfo name) Right Surround = Rs = CR = SR = Rs (MediaInfo name) Left Rear Surround = Lrs = BL = Lsr = SL = Lb (MediaInfo name) Right Rear Surround = Rrs = BR = Rsr = Rb (MediaInfo name)
I'm not sure I understand the question, but I believe that "back" channels are only involved if there are more than 5 distinct audio signals plus one low frequency signal. By way of explanation, I believe that 5 distinct audio signals plus one low frequency signal is the configuration commonly referred to as "5.1" audio (front left, front right, center, side left, side right, and low frequency). I don't believe that the term "5.1" when used to describe an audio standard (summarized as the description of speaker locations listed in my previous sentence) specifies any "back' audio signals at all. If you wish to convert 5.1 audio to an audio format having more distinct signals or sends, then I think it is up to you to determine how you would like to distribute the audio signals to make use of the additional available channels. Did I say anything useful, or have I just confused the issue?
LL
_______________________________________________
Thank you for your answer. The point is that ffmpeg and MediaInfo do not output the same answer for the channels positions. Side is not Back particularly in the last century with quadrophonic. Or the information embedded in the file is confusing or one of the two programs decipher the embedded info in a wrong way. It could be interesting to know what is effectively coded inside the file and as well how the 2 programs decipher and output that data to understand the difference. Moreover, to get an accurate knowledge on ffmpeg, it could be interesting to copy the table https://mediaarea.net/AudioChannelLayout in the ffmpeg documentation and add one column with the corresponding ffmpeg output. MrNice
For your specific case, one would need to look at flac specification, and check does ffmpeg follow specification correctly. On Wed, Jan 29, 2025 at 10:24 AM MrNice <wxcvbn2006@iol.ie> wrote:
On Jan 28, 2025, at 4:14 PM, MrNice <wxcvbn2006@iol.ie> wrote:
On 28/01/2025 18:26, Carl Zwanzig wrote:
On 1/28/2025 8:18 AM, MrNice wrote:
have an audio file, with MediaInfo I get Audio Channel layout : L R Ls Rs
ffmpeg -v error -layouts | awk '/quad /{print $2}' FL+FR+BL+BR What is the correct answer? Both. Left, assumed to be front (L) = Front Left (FL) Left surround/side (Ls) = Back Left (BL) etc
(that's part way down the AudioChannelManipulation page, even farther down is a list of the channel names and standard layouts, also in the -layouts output)
z!
_______________________________________________ Are you sure for good Carl?
AFAIK, LS is surround and BL is back/Rear
Please look here
https://mediaarea.net/AudioChannelLayout
They say, depending of standardization; Left Surround = Ls = CL = SL = Ls (MediaInfo name) Right Surround = Rs = CR = SR = Rs (MediaInfo name) Left Rear Surround = Lrs = BL = Lsr = SL = Lb (MediaInfo name) Right Rear Surround = Rrs = BR = Rsr = Rb (MediaInfo name)
I'm not sure I understand the question, but I believe that "back" channels are only involved if there are more than 5 distinct audio signals plus one low frequency signal. By way of explanation, I believe that 5 distinct audio signals plus one low frequency signal is the configuration commonly referred to as "5.1" audio (front left, front right, center, side left, side right, and low frequency). I don't believe that the term "5.1" when used to describe an audio standard (summarized as the description of speaker locations listed in my previous sentence) specifies any "back' audio signals at all. If you wish to convert 5.1 audio to an audio format having more distinct signals or sends, then I think it is up to you to determine how you would like to distribute the audio signals to make use of the additional available channels. Did I say anything useful, or have I just confused the issue?
LL
_______________________________________________
Thank you for your answer.
The point is that ffmpeg and MediaInfo do not output the same answer for the channels positions. Side is not Back particularly in the last century with quadrophonic.
Or the information embedded in the file is confusing or one of the two programs decipher the embedded info in a wrong way. It could be interesting to know what is effectively coded inside the file and as well how the 2 programs decipher and output that data to understand the difference.
Moreover, to get an accurate knowledge on ffmpeg, it could be interesting to copy the table https://mediaarea.net/AudioChannelLayout in the ffmpeg documentation and add one column with the corresponding ffmpeg output.
MrNice
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To unsubscribe, visit link above, or email ffmpeg-user-request@ffmpeg.org with subject "unsubscribe".
On 29/01/2025 11:26, Paul B Mahol wrote:
For your specific case, one would need to look at flac specification, and check does ffmpeg follow specification correctly.
On Wed, Jan 29, 2025 at 10:24 AM MrNice <wxcvbn2006@iol.ie> wrote:
On Jan 28, 2025, at 4:14 PM, MrNice <wxcvbn2006@iol.ie> wrote:
On 28/01/2025 18:26, Carl Zwanzig wrote:
On 1/28/2025 8:18 AM, MrNice wrote:
have an audio file, with MediaInfo I get Audio Channel layout : L R Ls Rs > ffmpeg -v error -layouts | awk '/quad /{print $2}' FL+FR+BL+BR What is the correct answer? Both. Left, assumed to be front (L) = Front Left (FL) Left surround/side (Ls) = Back Left (BL) etc
(that's part way down the AudioChannelManipulation page, even farther down is a list of the channel names and standard layouts, also in the -layouts output) z!
_______________________________________________ Are you sure for good Carl?
AFAIK, LS is surround and BL is back/Rear
Please look here
https://mediaarea.net/AudioChannelLayout
They say, depending of standardization; Left Surround = Ls = CL = SL = Ls (MediaInfo name) Right Surround = Rs = CR = SR = Rs (MediaInfo name) Left Rear Surround = Lrs = BL = Lsr = SL = Lb (MediaInfo name) Right Rear Surround = Rrs = BR = Rsr = Rb (MediaInfo name)
I'm not sure I understand the question, but I believe that "back" channels are only involved if there are more than 5 distinct audio signals plus one low frequency signal. By way of explanation, I believe that 5 distinct audio signals plus one low frequency signal is the configuration commonly referred to as "5.1" audio (front left, front right, center, side left, side right, and low frequency). I don't believe that the term "5.1" when used to describe an audio standard (summarized as the description of speaker locations listed in my previous sentence) specifies any "back' audio signals at all. If you wish to convert 5.1 audio to an audio format having more distinct signals or sends, then I think it is up to you to determine how you would like to distribute the audio signals to make use of the additional available channels. Did I say anything useful, or have I just confused the issue? LL
_______________________________________________ Thank you for your answer.
The point is that ffmpeg and MediaInfo do not output the same answer for the channels positions. Side is not Back particularly in the last century with quadrophonic.
Or the information embedded in the file is confusing or one of the two programs decipher the embedded info in a wrong way. It could be interesting to know what is effectively coded inside the file and as well how the 2 programs decipher and output that data to understand the difference.
Moreover, to get an accurate knowledge on ffmpeg, it could be interesting to copy the table https://mediaarea.net/AudioChannelLayout in the ffmpeg documentation and add one column with the corresponding ffmpeg output.
MrNice
_______________________________________________ ffmpeg-user mailing list ffmpeg-user@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-user
To unsubscribe, visit link above, or email ffmpeg-user-request@ffmpeg.org with subject "unsubscribe".
_______________________________________________
Unfortunately, I am not skilled enough in that matter to go this way. Is there de developer who could complete the table https://mediaarea.net/AudioChannelLayout With the ffmpeg/ffprobe output ?
Search for "surround" left/channel back. To me it looks the flac decoder is correct. https://datatracker.ietf.org/doc/rfc9639/ On Wed, Jan 29, 2025 at 4:37 PM MrNice <wxcvbn2006@iol.ie> wrote:
For your specific case, one would need to look at flac specification, and check does ffmpeg follow specification correctly.
On Wed, Jan 29, 2025 at 10:24 AM MrNice <wxcvbn2006@iol.ie> wrote:
On Jan 28, 2025, at 4:14 PM, MrNice <wxcvbn2006@iol.ie> wrote:
On 28/01/2025 18:26, Carl Zwanzig wrote:
On 1/28/2025 8:18 AM, MrNice wrote: > have an audio file, with MediaInfo I get > Audio > Channel layout : L R Ls Rs > > ffmpeg -v error -layouts | awk '/quad /{print $2}' > FL+FR+BL+BR > What is the correct answer? Both. Left, assumed to be front (L) = Front Left (FL) Left surround/side (Ls) = Back Left (BL) etc
(that's part way down the AudioChannelManipulation page, even farther down is a list of the channel names and standard layouts, also in the -layouts output) z!
_______________________________________________ Are you sure for good Carl?
AFAIK, LS is surround and BL is back/Rear
Please look here
https://mediaarea.net/AudioChannelLayout
They say, depending of standardization; Left Surround = Ls = CL = SL = Ls (MediaInfo name) Right Surround = Rs = CR = SR = Rs (MediaInfo name) Left Rear Surround = Lrs = BL = Lsr = SL = Lb (MediaInfo name) Right Rear Surround = Rrs = BR = Rsr = Rb (MediaInfo name)
I'm not sure I understand the question, but I believe that "back" channels are only involved if there are more than 5 distinct audio signals plus one low frequency signal. By way of explanation, I believe that 5 distinct audio signals plus one low frequency signal is the configuration commonly referred to as "5.1" audio (front left, front right, center, side left, side right, and low frequency). I don't believe that the term "5.1" when used to describe an audio standard (summarized as the description of speaker locations listed in my previous sentence) specifies any "back' audio signals at all. If you wish to convert 5.1 audio to an audio
On 29/01/2025 11:26, Paul B Mahol wrote: format
having more distinct signals or sends, then I think it is up to you to determine how you would like to distribute the audio signals to make use of the additional available channels. Did I say anything useful, or have I just confused the issue?
LL
_______________________________________________ Thank you for your answer.
The point is that ffmpeg and MediaInfo do not output the same answer for the channels positions. Side is not Back particularly in the last century with quadrophonic.
Or the information embedded in the file is confusing or one of the two programs decipher the embedded info in a wrong way. It could be interesting to know what is effectively coded inside the file and as well how the 2 programs decipher and output that data to understand the difference.
Moreover, to get an accurate knowledge on ffmpeg, it could be interesting to copy the table https://mediaarea.net/AudioChannelLayout in the ffmpeg documentation and add one column with the corresponding ffmpeg output.
MrNice
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To unsubscribe, visit link above, or email ffmpeg-user-request@ffmpeg.org with subject "unsubscribe".
_______________________________________________
Unfortunately, I am not skilled enough in that matter to go this way.
Is there de developer who could complete the table
https://mediaarea.net/AudioChannelLayout
With the ffmpeg/ffprobe output ?
_______________________________________________ ffmpeg-user mailing list ffmpeg-user@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-user
To unsubscribe, visit link above, or email ffmpeg-user-request@ffmpeg.org with subject "unsubscribe".
Also note that still channel layouts in FFmpeg do not store/signal anywhere real channel horizontal/vertical angle. On Wed, Jan 29, 2025 at 4:46 PM Paul B Mahol <onemda@gmail.com> wrote:
Search for "surround" left/channel back. To me it looks the flac decoder is correct.
https://datatracker.ietf.org/doc/rfc9639/
On Wed, Jan 29, 2025 at 4:37 PM MrNice <wxcvbn2006@iol.ie> wrote:
For your specific case, one would need to look at flac specification, and check does ffmpeg follow specification correctly.
On Wed, Jan 29, 2025 at 10:24 AM MrNice <wxcvbn2006@iol.ie> wrote:
On Jan 28, 2025, at 4:14 PM, MrNice <wxcvbn2006@iol.ie> wrote:
On 28/01/2025 18:26, Carl Zwanzig wrote: > On 1/28/2025 8:18 AM, MrNice wrote: >> have an audio file, with MediaInfo I get >> Audio >> Channel layout : L R Ls Rs >> > ffmpeg -v error -layouts | awk '/quad /{print $2}' >> FL+FR+BL+BR >> What is the correct answer? > Both. > Left, assumed to be front (L) = Front Left (FL) > Left surround/side (Ls) = Back Left (BL) > etc > > (that's part way down the AudioChannelManipulation page, even farther down is a list of the channel names and standard layouts, also in the -layouts output) > z! > > _______________________________________________ Are you sure for good Carl?
AFAIK, LS is surround and BL is back/Rear
Please look here
https://mediaarea.net/AudioChannelLayout
They say, depending of standardization; Left Surround = Ls = CL = SL = Ls (MediaInfo name) Right Surround = Rs = CR = SR = Rs (MediaInfo name) Left Rear Surround = Lrs = BL = Lsr = SL = Lb (MediaInfo name) Right Rear Surround = Rrs = BR = Rsr = Rb (MediaInfo name)
I'm not sure I understand the question, but I believe that "back" channels are only involved if there are more than 5 distinct audio signals plus one low frequency signal. By way of explanation, I believe that 5 distinct audio signals plus one low frequency signal is the configuration commonly referred to as "5.1" audio (front left, front right, center, side left, side right, and low frequency). I don't believe that the term "5.1" when used to describe an audio standard (summarized as the description of speaker locations listed in my previous sentence) specifies any "back' audio signals at all. If you wish to convert 5.1 audio to an audio
On 29/01/2025 11:26, Paul B Mahol wrote: format
having more distinct signals or sends, then I think it is up to you to determine how you would like to distribute the audio signals to make use of the additional available channels. Did I say anything useful, or have I just confused the issue?
LL
_______________________________________________ Thank you for your answer.
The point is that ffmpeg and MediaInfo do not output the same answer for the channels positions. Side is not Back particularly in the last century with quadrophonic.
Or the information embedded in the file is confusing or one of the two programs decipher the embedded info in a wrong way. It could be interesting to know what is effectively coded inside the file and as well how the 2 programs decipher and output that data to understand the difference.
Moreover, to get an accurate knowledge on ffmpeg, it could be interesting to copy the table https://mediaarea.net/AudioChannelLayout in the ffmpeg documentation and add one column with the corresponding ffmpeg output.
MrNice
_______________________________________________ ffmpeg-user mailing list ffmpeg-user@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-user
To unsubscribe, visit link above, or email ffmpeg-user-request@ffmpeg.org with subject "unsubscribe".
_______________________________________________
Unfortunately, I am not skilled enough in that matter to go this way.
Is there de developer who could complete the table
https://mediaarea.net/AudioChannelLayout
With the ffmpeg/ffprobe output ?
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