Freeview (Quick) Update: 7flix now with MPEG-1 audio as well!

Due to the poor user response, it seems that Channel 7 has, as I had predicted it would, partially done a backflip with 7flix’s audio.

That being said, if they were really nice, they should probably split out another 128kbit/s from the video stream and just change over to 192kbit/s MPEG-1 Joint-Stereo just to make sure everyone can hear it because there are quite a few sets which can deal with H.264 but not AAC-HEv2.

Gough Lui  (February 29, 2016 at 8:47 pm)

As noted by some others who have found that they are now receiving audio on the service, there is now a second audio stream attached to 7flix which runs MPEG-1 Audio (PID 595) at 128kbit/s Joint-Stereo mode. The original AAC-HEv2 audio still continues on PID 594, but with reduced payload bitrate to ~48kbit/s from the original 64kbit/s.

The dump of the PMT from TSReader clearly shows this is the case:

Program Number: 76/1317
PCR on PID 593 (0x0251)
PMT Version: 20
Service name: 7flix
Logical channel number: 76

Stream Type: 0x05 ISO/IEC 13818-1 private_sections
 Elementary Stream PID 518 (0x0206)

Stream Type: 0x1b H.264 Video
 Elementary Stream PID 593 (0x0251)

Stream Type: 0x11 MPEG-4 Audio
 Elementary Stream PID 594 (0x0252)

Stream Type: 0x03 MPEG-1 Audio
 Elementary Stream PID 595 (0x0253)

Stream Type: 0x06 Teletext/VBI
 Elementary Stream PID 596 (0x0254)

Stream Type: 0x0b ISO/IEC 13818-6 type B
 Elementary Stream PID 665 (0x0299)

… when combined with the “spot” bitrates, as I haven’t the time to spend on a full analysis:

spot-bitrates

On the whole, bitrate allocation seems fairly similar, although it seems 7mate may have lost a tiny amount to make this happen, rather than 7flix shaving its generous H.264 video bitrate.

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2 Responses to Freeview (Quick) Update: 7flix now with MPEG-1 audio as well!

  1. Greg says:

    Didn’t last long. Looks like they went back to a single HE-AAC audio stream in Sydney. Seems they don’t want a larger audience for their advertisers.

    • lui_gough says:

      Thanks for that update Greg.

      Indeed it is true, and disappointing, but I suppose they might still change things in the months to come, especially as we are expecting their eventual launch of 7 HD simulcast.

      – Gough

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