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Transcoding combinations UPnP and Internet Radio
12-03-2015, 12:19
Post: #1
Transcoding combinations UPnP and Internet Radio
I have struggling to understand the different transcoding combinations available. Apologies for the length of the following, but I would be grateful if someone could confirm, or correct, my understanding.

So this is an attempt to understand the subtleties of transcoding with UPnP and Internet Radio. I will only mention aac and 'unspecified' stream types where the underlying type is in fact aac, for the sake of simplicity. I believe other stream types will all follow the same logic as that for aac.

1. Internet Radio Only

If the only service used is Internet Radio, no transcoding should be specified at all. However, I believe a converter like ffmpeg or avconv may still be needed for HLS streams.

2. UPnP Streams Only

If the only radio service used is Internet Radio streaming via UPnP, then I believe the options are as follows:

a) aac is specified in the stream url or in the m3u file

aac:L16/wav24/-

- aac can be transcoded to any one of the supported output stream types (eg. L16 or wav24), and also made available unchanged (-). A '^' has no effect since the Control Point or Renderer makes the choice, not minimstreamer.

*:L16/wav24/-

- has no effect, since the codec is known

b) aac is not specified, but minimstreamer finds out that it is aac on inspection:

aac:L16/wav24/-

- the Control Point or renderer will choose amongst the defined codecs

aac:L16/wav24^/-

- minimstreamer will always transcode to wav24 (I can't see why this is a useful combination, why not just use aac:wav24? )

*:L16/wav24/-

- the Control Point or renderer will choose amongst the defined codecs

*:L16/wav24^/-

- as above - the '^' has no effect since '*' is specified

3. Both Internet Radio and UPnP devices available

a) aac is specified in the stream url or in the m3u file

aac:L16/wav24/-

- for UPnP, aac can be transcoded to any one of the supported output stream types (eg. L16 or wav24), and also made available unchanged (-).
- what happens for Internet Radio? Does it fail?

aac:L16/wav24/-^

- for UPnP, aac can be transcoded to any one of the supported output stream types (eg. L16 or wav24), and also made available unchanged (-).
- for Internet Radio no transcoding will take place.

*:L16/wav24/-

- has no effect, since the codec is known

*:L16/wav24/-^

- has no effect, since the codec is known

b) aac is not specified, but minimstreamer finds out that it is aac on inspection:

aac:L16/wav24/-

- for UPnP, minimstreamer will default to L16 – I'm not sure if the other values have any effect at all?
- what happens for Internet Radio? Does it fail?

aac:L16/wav24/-^

- for UpnP, minimstreamer will default to no transcoding – I'm not sure if the other values have any effect at all?
- for Internet Radio no transcoding will take place

*:L16/wav24/-

- for UPnP, aac can be transcoded to any one of the supported output stream types (eg. L16 or wav24), and also made available unchanged (-).
- what happens for Internet Radio? Does it fail?

*:L16/wav24/-^

- for UPnP, aac can be transcoded to any one of the supported output stream types (eg. L16 or wav24), and also made available unchanged (-).
- for Internet Radio no transcoding will take place.
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12-03-2015, 21:12
Post: #2
RE: Transcoding combinations UPnP and Internet Radio
I prepared this early but didn't post in case Simon appeared in the meantime...

Probably should not put my two pennies worth in since Simon's the expert, his product etc. But you did say "somebody".

On 1. No you don't need to transcode if HLS stream if your system can handle AAC internet radio. MinimStreamer by default unpacks HLS to AAC without any transcode command. So on a Denon network player (720) no transcode was required since it plays AAC. It's what you interface to that, that requires the transcode, if it doesn't work in that native form then it needs transcoding.

That's a no too "However, I believe a converter like ffmpeg or avconv may still be needed for HLS streams. " unless there is something odd about the player not playing the AAC streams from HLS.

The high end systems may only interface via the transcode L16 and wav24 etc which is why Simon has these transcodes liberally shown and talked about. The multiple ones are for where you have several systems on the network as I understand it and the "-" is where your system can handle it without transcode if you need to transcode for other equipment on the network.

That's this page of the manual:

http://minimstreamer.com/userguide.html#Transcoding

At this point I'm going to duck out as it gets complicated if you have a complex system and not just a standard network player Smile. But sufficient to say if your system previously played the BBC AAC it should play the output of Minimstream without transcoding unless transcoding was already taking place. The transferring of the transcode only shifts where the place of converting the digital compressed stream (if compressed) into a digital form via those output parameters excluding MP3, you might have to do it since your system can't handle it in it's native form or it's better to do it for reasons of processing and digital quality at higher rates. Thus those that may wish to record or take advantage of what their system has to offer at the higher digital rates can make use of some of the more enhanced parameters for transcoding in the software. (I don't own such a system so that doesn't apply to me)

Simon's "*" parameter means transcode all irrespective you would do that liberally if that's the only way to get it into your system or decided that you wished to get a more specific data stream into your system.

On the ^ Simon says in the manual

>>
By default, MinimStreamer chooses the first output type in the list. You can override this default choice by adding a ^ (caret) character after the output type that you want MinimStreamer to choose. For example, the transcoding combination aac:L16/wav24^ tells MinimStreamer to choose wav24 if it discovers that the network stream type is AAC.
<<

What he means there is that wav24 will give better justice to the sound.... this is what comes of having a high end system with bells and whistles. I would say looking at the table if your system can handle WAV24 then that would be the one to use. I stand to be corrected.
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12-03-2015, 21:26
Post: #3
RE: Transcoding combinations UPnP and Internet Radio
Thanks.
(12-03-2015 21:12)Tell Wrote:  I prepared this early but didn't post in case Simon appeared in the meantime...

Probably should not put my two pennies worth in since Simon's the expert, his product etc. But you did say "somebody".

On 1. No you don't need to transcode if HLS stream if your system can handle AAC internet radio. MinimStreamer by default unpacks HLS to AAC without any transcode command. So on a Denon network player (720) no transcode was required since it plays AAC. It's what you interface to that, that requires the transcode, if it doesn't work in that native form then it needs transcoding.

That's a no too "However, I believe a converter like ffmpeg or avconv may still be needed for HLS streams. " unless there is something odd about the player not playing the AAC streams from HLS.
My understanding, which may be wrong, is that no transcoding for Internet Radio is available. There is for UPnP, but not Internet Radio. I may be wrong, but that's one of the things I'm trying to find out.

Quote:The high end systems may only interface via the transcode L16 and wav24 etc which is why Simon has these transcodes liberally shown and talked about. The multiple ones are for where you have several systems on the network as I understand it and the "-" is where your system can handle it without transcode if you need to transcode for other equipment on the network.

That's this page of the manual:

http://minimstreamer.com/userguide.html#Transcoding
I believe that is only for UPnP, not Internet Radio devices, but I may be wrong.
Quote:At this point I'm going to duck out as it gets complicated if you have a complex system and not just a standard network player Smile. But sufficient to say if your system previously played the BBC AAC it should play the output of Minimstream without transcoding unless transcoding was already taking place. The transferring of the transcode only shifts where the place of converting the digital compressed stream (if compressed) into a digital form via those output parameters excluding MP3, you might have to do it since your system can't handle it in it's native form or it's better to do it for reasons of processing and digital quality at higher rates. Thus those that may wish to record or take advantage of what their system has to offer at the higher digital rates can make use of some of the more enhanced parameters for transcoding in the software. (I don't own such a system so that doesn't apply to me)
I feel I need to understand what is possible, and what it all means, and then I can decide. Currently I am puzzled.

Quote:Simon's "*" parameter means transcode all irrespective you would do that liberally if that's the only way to get it into your system or decided that you wished to get a more specific data stream into your system.
There might be something I don't know about, that could be transcoded to something I do know, but only for UPnP - I think...

Quote:On the ^ Simon says in the manual

>>
By default, MinimStreamer chooses the first output type in the list. You can override this default choice by adding a ^ (caret) character after the output type that you want MinimStreamer to choose. For example, the transcoding combination aac:L16/wav24^ tells MinimStreamer to choose wav24 if it discovers that the network stream type is AAC.
<<
I fail to understand what this example does in all cases, which is why I have tried to list all options to see what happens in each case. It is far from obvious, to me at any rate.
Quote:What he means there is that wav24 will give better justice to the sound.... this is what comes of having a high end system with bells and whistles. I would say looking at the table if your system can handle WAV24 then that would be the one to use. I stand to be corrected.
wav24 will work well for UPnP on some devices, although not all. getting the system to pick it in all cases is something that I've found hard to work out. Again, that's partly why I have tried to show each case and pose answers.
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12-03-2015, 22:05
Post: #4
RE: Transcoding combinations UPnP and Internet Radio
Well no on the first one it should work with any internet radio station the HLS processing is an enhancement built into MinimStreamer.

I think you need to study the manual for your system and decide which is the ideal input form then aim for that. If you have a range of receivers then that's more tricky. Seems like you have wav24 so that's the one to aim for.

Over to Simon, dinner awaits.
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12-03-2015, 22:21
Post: #5
RE: Transcoding combinations UPnP and Internet Radio
(12-03-2015 22:05)Tell Wrote:  Well no on the first one it should work with any internet radio station the HLS processing is an enhancement built into MinimStreamer.

I think you need to study the manual for your system and decide which is the ideal input form then aim for that. If you have a range of receivers then that's more tricky. Seems like you have wav24 so that's the one to aim for.

Over to Simon, dinner awaits
I have 2 UPnP renderers, and had been thinking of getting an Internet radio device for another room. So I'd need to set up a solution that work for all devices, and I need to understand how all these things interact. I have spent a lot of time trying to understand, but am clearly not clever enough, so I had to try to lay out each case and wonder what it meant. I have been told it is really simple, so somehow I've lost the plot. Still, I don't want to buy a device and find I can't get it to work, what with the BBC's mucking about lately.

As to ffmpeg/avconv etc, I thought minimstreamer was using it to handle HLS (regardlsess of audio codec issues). I may well be wrong.
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12-03-2015, 23:56
Post: #6
RE: Transcoding combinations UPnP and Internet Radio
(12-03-2015 12:19)Pastim Wrote:  I have struggling to understand the different transcoding combinations available. Apologies for the length of the following, but I would be grateful if someone could confirm, or correct, my understanding.

So this is an attempt to understand the subtleties of transcoding with UPnP and Internet Radio. I will only mention aac and 'unspecified' stream types where the underlying type is in fact aac, for the sake of simplicity. I believe other stream types will all follow the same logic as that for aac.

1. Internet Radio Only

If the only service used is Internet Radio, no transcoding should be specified at all. However, I believe a converter like ffmpeg or avconv may still be needed for HLS streams.

It shouldn't be needed for an internet radio, as this should be able to receive an untranscoded AAC ADTS stream (same as the previous BBC streams).

Quote:2. UPnP Streams Only

If the only radio service used is Internet Radio streaming via UPnP, then I believe the options are as follows:

a) aac is specified in the stream url or in the m3u file

This should always be specified in the m3u file, not by "hand-editing" the URL. If the URL doesn't match what's in the m3u file, the results are undefined. In what follows, I am assuming that it was specified in the m3u file.

Quote:aac:L16/wav24/-

- aac can be transcoded to any one of the supported output stream types (eg. L16 or wav24), and also made available unchanged (-). A '^' has no effect since the Control Point or Renderer makes the choice, not minimstreamer.

*:L16/wav24/-

- has no effect, since the codec is known

Correct.

Quote:b) aac is not specified, but minimstreamer finds out that it is aac on inspection:

aac:L16/wav24/-

- the Control Point or renderer will choose amongst the defined codecs

Not correct. The control point will see a single stream and MinimStreamer will choose L16.

Quote:
aac:L16/wav24^/-

- minimstreamer will always transcode to wav24 (I can't see why this is a useful combination, why not just use aac:wav24? )

Correct. It is a useful setting because you might have other streams of type a).

Quote:*:L16/wav24/-

- the Control Point or renderer will choose amongst the defined codecs

*:L16/wav24^/-

- as above - the '^' has no effect since '*' is specified

Correct.

Quote:3. Both Internet Radio and UPnP devices available

a) aac is specified in the stream url or in the m3u file

This should always be specified in the m3u file, not by "hand-editing" the URL. If the URL doesn't match what's in the m3u file, the results are undefined. In what follows, I am assuming that it was specified in the m3u file.

Quote:aac:L16/wav24/-

- for UPnP, aac can be transcoded to any one of the supported output stream types (eg. L16 or wav24), and also made available unchanged (-).

Correct.

Quote:- what happens for Internet Radio? Does it fail?

For internet radio, MinimStreamer will choose L16 (first in list). This might succeed if the internet radio can play an L16 stream.

Quote:aac:L16/wav24/-^

- for UPnP, aac can be transcoded to any one of the supported output stream types (eg. L16 or wav24), and also made available unchanged (-).

- for Internet Radio no transcoding will take place.

*:L16/wav24/-

- has no effect, since the codec is known

*:L16/wav24/-^

- has no effect, since the codec is known

Correct.

Quote:b) aac is not specified, but minimstreamer finds out that it is aac on inspection:

aac:L16/wav24/-

- for UPnP, minimstreamer will default to L16 – I'm not sure if the other values have any effect at all?

The control point will see a single stream and MinimStreamer will always choose L16.

Quote:- what happens for Internet Radio? Does it fail?

For internet radio, MinimStreamer will choose L16 (first in list). This might succeed if the internet radio can play an L16 stream.

Quote:aac:L16/wav24/-^

- for UpnP, minimstreamer will default to no transcoding – I'm not sure if the other values have any effect at all?

For this stream, the other values are ignored.

Quote:- for Internet Radio no transcoding will take place

*:L16/wav24/-

- for UPnP, aac can be transcoded to any one of the supported output stream types (eg. L16 or wav24), and also made available unchanged (-).

Correct.

Quote:- what happens for Internet Radio? Does it fail?

Internet radio will not be transcoded.

Quote:*:L16/wav24/-^

- for UPnP, aac can be transcoded to any one of the supported output stream types (eg. L16 or wav24), and also made available unchanged (-).
- for Internet Radio no transcoding will take place.

Correct.
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13-03-2015, 00:01 (This post was last modified: 13-03-2015 00:01 by simoncn.)
Post: #7
RE: Transcoding combinations UPnP and Internet Radio
(12-03-2015 21:12)Tell Wrote:  I prepared this early but didn't post in case Simon appeared in the meantime...

Probably should not put my two pennies worth in since Simon's the expert, his product etc. But you did say "somebody".

On 1. No you don't need to transcode if HLS stream if your system can handle AAC internet radio. MinimStreamer by default unpacks HLS to AAC without any transcode command. So on a Denon network player (720) no transcode was required since it plays AAC. It's what you interface to that, that requires the transcode, if it doesn't work in that native form then it needs transcoding.

That's a no too "However, I believe a converter like ffmpeg or avconv may still be needed for HLS streams. " unless there is something odd about the player not playing the AAC streams from HLS.

The high end systems may only interface via the transcode L16 and wav24 etc which is why Simon has these transcodes liberally shown and talked about. The multiple ones are for where you have several systems on the network as I understand it and the "-" is where your system can handle it without transcode if you need to transcode for other equipment on the network.

That's this page of the manual:

http://minimstreamer.com/userguide.html#Transcoding

At this point I'm going to duck out as it gets complicated if you have a complex system and not just a standard network player Smile. But sufficient to say if your system previously played the BBC AAC it should play the output of Minimstream without transcoding unless transcoding was already taking place. The transferring of the transcode only shifts where the place of converting the digital compressed stream (if compressed) into a digital form via those output parameters excluding MP3, you might have to do it since your system can't handle it in it's native form or it's better to do it for reasons of processing and digital quality at higher rates. Thus those that may wish to record or take advantage of what their system has to offer at the higher digital rates can make use of some of the more enhanced parameters for transcoding in the software. (I don't own such a system so that doesn't apply to me)

Yes, that's right.

Quote:Simon's "*" parameter means transcode all irrespective you would do that liberally if that's the only way to get it into your system or decided that you wished to get a more specific data stream into your system.

The * means "unspecified", not "all".

Quote:On the ^ Simon says in the manual

>>
By default, MinimStreamer chooses the first output type in the list. You can override this default choice by adding a ^ (caret) character after the output type that you want MinimStreamer to choose. For example, the transcoding combination aac:L16/wav24^ tells MinimStreamer to choose wav24 if it discovers that the network stream type is AAC.
<<

What he means there is that wav24 will give better justice to the sound.... this is what comes of having a high end system with bells and whistles. I would say looking at the table if your system can handle WAV24 then that would be the one to use. I stand to be corrected.

The caret can apply to any type (of higher or lower quality).
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13-03-2015, 00:05
Post: #8
RE: Transcoding combinations UPnP and Internet Radio
(12-03-2015 21:26)Pastim Wrote:  My understanding, which may be wrong, is that no transcoding for Internet Radio is available. There is for UPnP, but not Internet Radio. I may be wrong, but that's one of the things I'm trying to find out.

The aac: transcode settings apply to internet radio streams of type aac.

Quote:I believe that is only for UPnP, not Internet Radio devices, but I may be wrong.

See above.

Quote:There might be something I don't know about, that could be transcoded to something I do know, but only for UPnP - I think...

You are correct that the *: settings apply only to UPnP.
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13-03-2015, 00:06
Post: #9
RE: Transcoding combinations UPnP and Internet Radio
(12-03-2015 21:12)Tell Wrote:  I prepared this early but didn't post in case Simon appeared in the meantime...

Probably should not put my two pennies worth in since Simon's the expert, his product etc. But you did say "somebody".

On 1. No you don't need to transcode if HLS stream if your system can handle AAC internet radio. MinimStreamer by default unpacks HLS to AAC without any transcode command. So on a Denon network player (720) no transcode was required since it plays AAC. It's what you interface to that, that requires the transcode, if it doesn't work in that native form then it needs transcoding.

That's a no too "However, I believe a converter like ffmpeg or avconv may still be needed for HLS streams. " unless there is something odd about the player not playing the AAC streams from HLS.

I have two Reciva based internet radios that can play AAC radio streams. However I had to install ffmpeg and set the stream.transcode aac:L16 in order for the radios to play the BBC HLS streams. Without transcoding these streams were unplayable.
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13-03-2015, 00:07
Post: #10
RE: Transcoding combinations UPnP and Internet Radio
(12-03-2015 22:21)Pastim Wrote:  As to ffmpeg/avconv etc, I thought minimstreamer was using it to handle HLS (regardlsess of audio codec issues). I may well be wrong.

MinimStreamer has its own code to handle HLS. No other converter is needed.
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