On 07/08/16 09:32, Jim web wrote:
In article <[email protected]>, Alan
Milewczyk <[email protected]> wrote:
I have a very stable 200Mbps connection so I decided to test just how
bad the situation actually is. Overnight I carried out a download of 124
sample programmes drawn from BBC's One, Two and Four which were
broadcast between Monday and Friday. Of this sample, only 63 were
downloaded without fault (60 hlshd, 3 hlsvhigh). The remaining 61 had at
least one segment missing (58 hlshd, 3 hlsvhigh). A dreadful situation.
It is particularly annoying for me that it has arisen during the Proms.
On one hand, using the 'old' (RTMPDump/Flash) route is markedly slower.
Since I mainly get things before 9am to dodge using up my 'allowance' this
limits how much I can get at what is a 'busy time'
On the other, if I use the HLS I have to carefully check to see the result
is complete. I am also now worried by the possibility that some examples
I've not yet fully watched might havs problems at some point with synch,
etc. i.e. It may not be sufficient to ensure they seem about the correct
length. Particularly annoying for a musical concert where synch is vital.
If there is a synch problem due to missing chunks at some point, does that
persist or accumulate to the end of the file? i.e. if the synch is correct
at the end, does that indicate that it was probably OK thoughout?
I don't use the PVR as I find it's too much of a fag adding and removing
programmes for download so I use a combination of a batch file which
reads a text file containing the PIDs I want to download. With this
"dropped segments" situation I've started to pipe the output to an error
file. As some programmes might not be watched for a while, at least this
gives me notification of a problem so I can try again for faulty
programmes using RTMPDump/Flash. As you say the latter is much slower -
I'm getting between 30Mbps and 100Mbps for HLS but using Flash the same
programmes take, on average, four times longer than HLS.
It's a real eyeopener scanning the error file, some programmes have
multiple dropped segments - I've not bothered trying to play the files
to see how bad the synch issue actually is, I've re-downloaded using Flash.
I sympathise for anyone in your situation where you have constraints on
your downloading schedule, a real hassle.
To make things worse, the Lumpits mean there won't be any Proms on
broadcast TV for a few weeks, so iplayer is the only access for the TV
versions.
This does drift OT. But it has reminded me that one long-term wish/thought
I've had is to work out how to take an iplayer TV version of a Prom and
replace its audio stream with the 320k R3 version during the music. However
even if I knew how to do this, again I think synch would drift. Tests some
years ago showed clock drifts between TV and radio.
Jim
I think you'll be giving yourself a massive task trying to synchronise
radio and TV outputs, I couldn't imagine the time it would take to do
that task!
Best wishes
Alan
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