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Transcoding combinations UPnP and Internet Radio
13-03-2015, 00:11
Post: #11
RE: Transcoding combinations UPnP and Internet Radio
(13-03-2015 00:06)Zeewier Wrote:  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.

Did you follow the instructions on this page to set the MinimStreamer URLs as custom radio station URLs in the internet radio? This would send the internet radio an AAC ADTS stream which should be playable by any internet radio that could play the previous BBC AAC ADTS Shoutcast streams.
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13-03-2015, 00:35
Post: #12
RE: Transcoding combinations UPnP and Internet Radio
Simon, thanks very much for your detailed response. I'll need to go through it in more detail after some sleep, but I have two initial questions.

1. I had understood, and indeed thought I had read on a post somewhere, that for an Internet Radio (not a UPnP device) no transcoding ever took place. Am I wrong? The minimradio sites seem to make no mention of it.

2. Why is it useful for the behaviour to be so different depending on whether the codec is explicit or determined by Minimstreamer? Why should a user care how the codec is determined? Surely if it is aac (for instance) the I would want it treated in the same way however this was discovered? It seems to me to make life quite complicated to no apparent benefit. What have I missed?
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13-03-2015, 01:07
Post: #13
RE: Transcoding combinations UPnP and Internet Radio
(13-03-2015 00:11)simoncn Wrote:  
(13-03-2015 00:06)Zeewier Wrote:  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.

Did you follow the instructions on this page to set the MinimStreamer URLs as custom radio station URLs in the internet radio? This would send the internet radio an AAC ADTS stream which should be playable by any internet radio that could play the previous BBC AAC ADTS Shoutcast streams.

Yes I did follow those instructions. I said "Without transcoding these streams were unplayable", but what I meant was that playing those streams was very unreliable. The problem was that occasionally a BBC HLS stream (custom radio URL) would play the first time, but more often it would start only after 4 or more attempts. Or after selecting another station and then going back to the first one. With ffmpeg installed and aac:L16 a successful connection is made the first time. This is true both when custom radio URLs are used and when the radios are used as UPnP players. Problem solved!
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13-03-2015, 02:29
Post: #14
RE: Transcoding combinations UPnP and Internet Radio
One for Pastim, I think you should adopt an experimental approach rather than pre-conceiving what you need to do in advance. That may be what you are doing is working out what you are going to do rather than testing it out a bit at a time. Obviously for audio quality you can't always tell the difference so matching up against parameters of what the system is capable of doing and trying that first is better than opting for for something less. I sense you might not have had scientific experimental training. Think you might be taking a holistic systems approach rather than a reductionist approach. The latter, the principal of optimality is that a solution to part of the problem, is part of the solution to the whole problem. What would we do without decision theory... probably experiment. You cross one bridge at a time at a time is a good maxim for getting things working and completed rather than bothering and worrying about doing it. Moving on from management science...

Zeewier, I did have a problem with the recorded AAC that I made last week so I wasn't totally sure that there wasn't something "funny" about it. This was using the source recorded AAC produced by MinimStreamer from HLS, my Humax which does play AACs as if they are MP3s relabelled refused to play it - this isn't a true test since I am not too sure what liberties it takes but it does play the BBC iPlayer ones fine. So I took the stream with me and put it through the Denon, that didn't like it either. But saying that it has no issues well apart from the "catching up effect" (that Simon has given me something to try out to increase the buffer) that seems to occur with heavy internet traffic in playing the "live" AAC produced by MinimServer from HLS. Android Mediahouse works fine with the AAC and Windows Foobar2000 with upnp extension.
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13-03-2015, 09:38
Post: #15
RE: Transcoding combinations UPnP and Internet Radio
(13-03-2015 02:29)Tell Wrote:  One for Pastim, I think you should adopt an experimental approach rather than pre-conceiving what you need to do in advance. That may be what you are doing is working out what you are going to do rather than testing it out a bit at a time. Obviously for audio quality you can't always tell the difference so matching up against parameters of what the system is capable of doing and trying that first is better than opting for for something less. I sense you might not have had scientific experimental training. Think you might be taking a holistic systems approach rather than a reductionist approach. The latter, the principal of optimality is that a solution to part of the problem, is part of the solution to the whole problem. What would we do without decision theory... probably experiment. You cross one bridge at a time at a time is a good maxim for getting things working and completed rather than bothering and worrying about doing it. Moving on from management science...

Zeewier, I did have a problem with the recorded AAC that I made last week so I wasn't totally sure that there wasn't something "funny" about it. This was using the source recorded AAC produced by MinimStreamer from HLS, my Humax which does play AACs as if they are MP3s relabelled refused to play it - this isn't a true test since I am not too sure what liberties it takes but it does play the BBC iPlayer ones fine. So I took the stream with me and put it through the Denon, that didn't like it either. But saying that it has no issues well apart from the "catching up effect" (that Simon has given me something to try out to increase the buffer) that seems to occur with heavy internet traffic in playing the "live" AAC produced by MinimServer from HLS. Android Mediahouse works fine with the AAC and Windows Foobar2000 with upnp extension.

I would be interested to look at the recorded file that isn't working. Do you still have it?
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13-03-2015, 10:27
Post: #16
RE: Transcoding combinations UPnP and Internet Radio
(13-03-2015 02:29)Tell Wrote:  One for Pastim, I think you should adopt an experimental approach rather than pre-conceiving what you need to do in advance. That may be what you are doing is working out what you are going to do rather than testing it out a bit at a time. Obviously for audio quality you can't always tell the difference so matching up against parameters of what the system is capable of doing and trying that first is better than opting for for something less. I sense you might not have had scientific experimental training. Think you might be taking a holistic systems approach rather than a reductionist approach. The latter, the principal of optimality is that a solution to part of the problem, is part of the solution to the whole problem. What would we do without decision theory... probably experiment. You cross one bridge at a time at a time is a good maxim for getting things working and completed rather than bothering and worrying about doing it. Moving on from management science...
I can't test when I don't have the device I'm thinking of buying.

Furthermore, whilst I'm happy to tinker, I need to understand. When I say 'need', I am stupidly obsessive about it. It bothers me. As a (retired) technical architect I can't really go forward without a design I comprehend.
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13-03-2015, 10:27
Post: #17
RE: Transcoding combinations UPnP and Internet Radio
(13-03-2015 00:35)Pastim Wrote:  Simon, thanks very much for your detailed response. I'll need to go through it in more detail after some sleep, but I have two initial questions.

1. I had understood, and indeed thought I had read on a post somewhere, that for an Internet Radio (not a UPnP device) no transcoding ever took place. Am I wrong? The minimradio sites seem to make no mention of it.

This is because most internet radios should be able to play AAC streams without transcoding. The MinimRadio instructions are intended for people who have a internet radio that was previously playing BBC AAC streams and now want to move to the new HLS streams. They cover everything needed for this scenario without introducing additional complexity by mentioning things that aren't needed such as transcoding.

Quote:2. Why is it useful for the behaviour to be so different depending on whether the codec is explicit or determined by Minimstreamer? Why should a user care how the codec is determined? Surely if it is aac (for instance) the I would want it treated in the same way however this was discovered? It seems to me to make life quite complicated to no apparent benefit. What have I missed?

In the first release of MinimStreamer, the stream type and its transcoding setting (if any) were determined dynamically when the stream was selected for playing. This meant the control point and renderer didn't know in advance what type of stream to expect. Some UPnP control points and renderers handle this OK (e.g., Kinsky and the Linn DS) but many UPnP renderers can't handle this and need to know the stream type before they open the stream for playing.

To solve this problem, the following changes were made:

1) For nontranscoded streams, provide the ability to specify an explicit stream type in the m3u file which enables the stream type to be known in advance.

2) For transcoded streams, add the "*" input type which enables the output type to be known in advance even if the input type isn't known in advance.

In addition, support was added for sending multiple transcoded output streams for a single input stream.

The situation is now as follows:

A) If the stream type isn't specified explicitly, you can do the following:

i) Use the "*" transcoding input type with a single output type to give the control point a single stream type in advance

ii) Use the "*" transcoding input type with mulitple output types to give the control point a choice of stream types in advance

iii) Use the "aac" transcoding input type, so the control point gets a single stream of unknown type and MinimStreamer selects the output type when the stream is opened and the type becomes known (using the caret if specified)

iv) do nothing, so the control point gets a single untranscoded stream of unknown type

B) If the stream type is specified explicitly as "aac", you can do the following:

i) Use the "aac" transcoding input type with a single output type to give the control point a single stream type in advance

ii) Use the "aac" transcoding input type with mulitple output types to give the control point a choice of stream types in advance

iii) do nothing, so the control point gets a single untranscoded stream of known type "aac"

Note the overlap between the transcoding settings for B) i), B) ii) and A) iii). This overlap gives the "aac" input type setting a dual purpose that applies in both the A) and B) cases with different effects.
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13-03-2015, 10:32
Post: #18
RE: Transcoding combinations UPnP and Internet Radio
(13-03-2015 10:27)simoncn Wrote:  
(13-03-2015 00:35)Pastim Wrote:  I had understood, and indeed thought I had read on a post somewhere, that for an Internet Radio (not a UPnP device) no transcoding ever took place. Am I wrong? The minimradio sites seem to make no mention of it.

This is because most internet radios should be able to play AAC streams without transcoding. The MinimRadio instructions are intended for people who have a internet radio that was previously playing BBC AAC streams and now want to move to the new HLS streams. They cover everything needed for this scenario without introducing additional complexity by mentioning things that aren't needed such as transcoding.
So you are saying that transcoding can take place for Internet Radios, but doesn't (usually) need to. Is that correct?
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13-03-2015, 10:45
Post: #19
RE: Transcoding combinations UPnP and Internet Radio
(13-03-2015 10:32)Pastim Wrote:  So you are saying that transcoding can take place for Internet Radios, but doesn't (usually) need to. Is that correct?

Yes. This is what Zeewier is doing.
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13-03-2015, 10:46 (This post was last modified: 13-03-2015 10:46 by simoncn.)
Post: #20
RE: Transcoding combinations UPnP and Internet Radio
(13-03-2015 01:07)Zeewier Wrote:  Yes I did follow those instructions. I said "Without transcoding these streams were unplayable", but what I meant was that playing those streams was very unreliable. The problem was that occasionally a BBC HLS stream (custom radio URL) would play the first time, but more often it would start only after 4 or more attempts. Or after selecting another station and then going back to the first one. With ffmpeg installed and aac:L16 a successful connection is made the first time. This is true both when custom radio URLs are used and when the radios are used as UPnP players. Problem solved!

I would be very interested to see a debug log for a failed attempt to connect. Would you be willing to to this? If so, I will post instructions.
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