Repeated use of time stretch adjustment has rounding error

[amb@…]

When repeatedly adjusting the time stretch (faster and then slower) it can introduce a rounding error due to the use of floating point without re-quantisation. For example the on-screen display of the time stretch can show weird numbers like "1.0499999995" instead of "1.05".

[Stuart Auchterlonie]

Moving remaining open tickets to 0.28.2 milestone

[Stuart Auchterlonie]

Moving remaining open tickets to 29.2 milestone

[Klaas de Waal]

The problem has been reproduced on today's master. The fix as given, with minor modifications to avoid compiler warnings, does remove the floating point error accumulation inherent in repeated additions and subtractions. The fix as tested is here:

    ctx->m_tsNormal = 0.05*(int)(new_ts_normal * 20.0F + 0.5F);

However, this does still not guarantee that the displayed value is limited to two decimal places. This can be specified in the QString::number conversion that is used to generate the string for presentation, as applied in the actual code here:

            UpdateOSDStatus(ctx, tr("Adjust Time Stretch"), tr("Time Stretch"),
                            QString::number(ctx->m_tsNormal,'f',2),
                            kOSDFunctionalType_TimeStretchAdjust, "X",
                            (int)(ctx->m_tsNormal*(1000/kTimeStretchMax)),
                            kOSDTimeout_None);

An additional benefit of having always two decimal places is that the "Time Stretch..." portion of the message "Adjust Time Stretch....Time Stretch 1.10X" presentation has a stable position on the screen because of the fixed length of the string.

[Klaas de Waal <kdewaal@…>]

In dae831860b/mythtv:

Error: Processor CommitTicketReference failed

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