Attention is currently required from: neels, laforge.

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2 comments:

• File src/trau/trau_rtp_conv.c:

  • Patch Set #1, Line 282:

    } else if (data_len == 0) {
    		/* C1 .. C5: idle speech */
    		tf->c_bits[0] = 0;
    		tf->c_bits[1] = 1;
    		tf->c_bits[2] = 1;
    		tf->c_bits[3] = 1;
    		tf->c_bits[4] = 0;
    

    Please read the rules of TS 48.060, particularly sections 6.5.2 and 6.5.3. Here is a bullet-point summary of these rules:

    • In the case of DL, for both FR and EFR, there is no choice: the TRAU must send an idle speech frame, which is distinguished from a regular speech frame by a unique C1..C5 pattern.
    • In the case of UL for EFR, the CCU must send a regular EFR speech frame (not idle speech frame) with BFI=1 - once again, no choice given.
    • In the case of UL for FR, the CCU has the option of sending either a regular speech frame with BFI=1 or an idle speech frame.

    Thus there is only one case where we as implementors get a choice: the case of FR UL. My patch implements the option of sending BFI=1, consistently with EFR when such behaviour is required. So let's decide on this issue first, before arguing over code structure: should we send a speech frame with BFI=1 or an idle speech frame in this case?

    Also @laforge wrote:

    Basically above where the "FIXME: Generate SID frames?" comment is (which is no longer a FIXME then.

    This FIXME is fixed, and that comment removed, in the second patch of the series.

  • Patch Set #1, Line 441: if (data_len == 0 && tf->dir == OSMO_TRAU_DIR_DL) {

    (wondering as above: why only for DL?)

    In the present case (EFR codec) the answer to the "why" question is straightforward: because TS 48.060 section 6.5.3 says so.

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