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 <wxcvbn2...@iol.ie> wrote: > >> On Jan 28, 2025, at 4:14 PM, MrNice <wxcvbn2...@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-requ...@ffmpeg.org with subject "unsubscribe". > _______________________________________________ ffmpeg-user mailing list ffmpeg-user@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-user To unsubscribe, visit link above, or email ffmpeg-user-requ...@ffmpeg.org with subject "unsubscribe".