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SD .ts files playback without transcoding

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  1. grahamlthompson

    grahamlthompson

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    larkim - 5 mins ago  » 
    User id by default is "aura" and pwd "0000" so maybe thtat's the issue, rather than using humaxftp as the username?

    Brilliant - I am in. Humaxftp is the name used by all the other Humax kit with FTP servers.

    | Thu 28 Jan 2021 15:08:48 #21 |
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    larkim

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    Original .ts 544x576 MPEG2
    Converted .ts 756x572 H264

    So on that basis I suspect it would cause all SD recordings to increase in size.

    | Thu 28 Jan 2021 15:13:16 #22 |
  3. grahamlthompson

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    larkim - 1 hour ago  » 
    Original .ts 544x576 MPEG2
    Converted .ts 756x572 H264
    So on that basis I suspect it would cause all SD recordings to increase in size.

    It should be smaller. The small increase in pixels should be more than compensated by the efficiency of the AVC encoder.

    544 x 576 is one of the poor quality SD channels. The BBC ones are all 720 x 576.

    The BBC HD encoder only uses a bitrate of a around 7000kbps. That's the bitrate used by the very best SD channels of a few years ago.

    I will have to record something on BBC1 to play further. All my recordings are from the HD channels.

    I have set a one off on pointless later today.

    | Thu 28 Jan 2021 16:22:46 #23 |
  4. grahamlthompson

    grahamlthompson

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    BBC 1 - SD recording source 720 x 576 downloaded using ftp is 544 x 576 mpeg 2 video compressed with two audio tracks plus DVB subtitles, Guessing one is the main stereo track and the the other the audio described track for the visually impaired

    I will compare with same file downloaded from the Web Interface

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    1. FTP_transfer_from_SD_recording.txt (4.4 KB, 1 downloads) 3 years old
    | Fri 29 Jan 2021 10:05:01 #24 |
  5. grahamlthompson

    grahamlthompson

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    This is interesting for the test recording.

    FTP created a much larger file at 1,20 GB Bitrate 3246Kbps. when you use ftp the file continues to increase in size for a long time after it says 100%. Suggests a bug in the FTP server

    Same programme using Webif. 771 MB Bitrate 2402kbps.

    Both look identical played back using a windows media player app (Splash).

    | Fri 29 Jan 2021 11:25:43 #25 |
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    larkim

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    When you say FTP created a larger file, what do you mean? The FTP folders I presume are just exposing the raw file system of the .ts recordings which are then played back when you use the TV interface. If you've selected conversion either through the TV interface or the mobile interfact or through the webpage view then you get a separate copy of the programme visible in the FTP file structure (though only in two of the folder views, not the first - can't remember the names of them just now as I'm at work). The original file is xxxxxxx.ts and the new one xxxxxx_conv.ts

    I'd assume (though would need to test) that the _conv.ts file is the one that either the app or the web interface would allow to be downloaded.

    I tried amending the resolution of converted recordings last night using the web interface; discovered I could only reduce the resolution from the 720x576 default, I quite fancied trying higher and lower to see what difference it made with no bitrate changes, and then making changes to the bitrate only, and thus finding a sweetspot with the biggest file size reduction and satisfactory usablity of the recording.

    | Fri 29 Jan 2021 14:42:02 #26 |
  7. grahamlthompson

    grahamlthompson

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    larkim - 23 mins ago  » 
    When you say FTP created a larger file, what do you mean? The FTP folders I presume are just exposing the raw file system of the .ts recordings which are then played back when you use the TV interface. If you've selected conversion either through the TV interface or the mobile interfact or through the webpage view then you get a separate copy of the programme visible in the FTP file structure (though only in two of the folder views, not the first - can't remember the names of them just now as I'm at work). The original file is xxxxxxx.ts and the new one xxxxxx_conv.ts
    I'd assume (though would need to test) that the _conv.ts file is the one that either the app or the web interface would allow to be downloaded.
    I tried amending the resolution of converted recordings last night using the web interface; discovered I could only reduce the resolution from the 720x576 default, I quite fancied trying higher and lower to see what difference it made with no bitrate changes, and then making changes to the bitrate only, and thus finding a sweetspot with the biggest file size reduction and satisfactory usablity of the recording.

    If you mean the transcoding bitrate options. I have already tried the default and maximum. Makes no difference to the quality as far as I can see.

    What I meant is exactly what I said.

    I recorded a test programme on BBC-1 (not having any SD ones).

    I downloaded a copy using the web interface.

    I downloaded a second copy using FTP.

    The one downloaded using FTP is much larger than the one from the webif.

    Guessing it contains lots of superflous data. Already known from the HDR-FOX-T2 is that downloaded files contain lots of data not needed. The files can be shrunk with zero effect on quality.

    Playing both they look identical despite the ftp one being much larger.

    | Fri 29 Jan 2021 15:11:39 #27 |
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    larkim

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    That's odd though - why would the HDD store 2x copies of the same file?

    It doesn't make sense for the HDD to be storing the original (HD broadcast) AND a "converted for mobile" version AND a different version for FTP purposes.

    But as you've said you can watch both of them, it can't be that you've downloaded the HD one as that would be encrypted, so that's truly odd!!

    Really peculiar, will play around on a similar basis myself tonight.

    In terms of transcoding options, no - I really do mean I've amended the resolution. On the "settings" page for the webinterface there is an option to edit the H and V resolutions, as well as manually editing the transcoding bitrate. From the TV interface you can only amend the transcoding bitrate, so I thought I'd play around with the other options. Not had a proper chance to look at the outputs yet though to see whether changing the resolution figures actually did change the resolution of the transcoded file.

    | Fri 29 Jan 2021 15:29:31 #28 |
  9. grahamlthompson

    grahamlthompson

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    larkim - 1 hour ago  » 
    That's odd though - why would the HDD store 2x copies of the same file?
    It doesn't make sense for the HDD to be storing the original (HD broadcast) AND a "converted for mobile" version AND a different version for FTP purposes.
    But as you've said you can watch both of them, it can't be that you've downloaded the HD one as that would be encrypted, so that's truly odd!!
    Really peculiar, will play around on a similar basis myself tonight.
    In terms of transcoding options, no - I really do mean I've amended the resolution. On the "settings" page for the webinterface there is an option to edit the H and V resolutions, as well as manually editing the transcoding bitrate. From the TV interface you can only amend the transcoding bitrate, so I thought I'd play around with the other options. Not had a proper chance to look at the outputs yet though to see whether changing the resolution figures actually did change the resolution of the transcoded file.

    I copied the recordings to different folders as I downloaded them so I was able to confirm the differences.

    I had forgotten that option, Gave up when it would no accept 1920 x 1080

    | Fri 29 Jan 2021 16:37:15 #29 |
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    larkim

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    Just downloaded a converted file three ways. Via FTP, via the web form, and via the app. All three resulted in bit-for-bit identical files being downloaded. Will play with some more but that result contradicts yours.

    In terms of downloading via the app, I found a folder on my phone where it was being downloaded to:
    Internal Storage/Android/data/com.humaxdigital.freeview/files/downloads

    FTP gave a faster download speed but that might have been a blip.

    | Fri 29 Jan 2021 18:32:20 #30 |

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