private uint CalculateNumDeltaPictureOrderCounts(IList <ShortTermRefPicSet> refPicSets, uint stRpsIdx, ShortTermRefPicSet result)
{
uint numDeltaPocs = 0;
int refRpsIdx = (int)(stRpsIdx - (result.delta_idx_minus1 + 1));
if (refPicSets[refRpsIdx].inter_ref_pic_set_prediction_flag)
{
for (int i = 0; i < refPicSets[refRpsIdx].used_by_curr_pic_flag.Count; i++)
{
if (refPicSets[refRpsIdx].used_by_curr_pic_flag[i] || refPicSets[refRpsIdx].use_delta_flag[i])
{
numDeltaPocs++;
}
}
}
else
{
numDeltaPocs = refPicSets[refRpsIdx].num_negative_pics + refPicSets[refRpsIdx].num_positive_pics;
}
return(numDeltaPocs);
}
/// <summary>
/// Process the short term reference picture sets.
/// </summary>
/// <remarks>
/// Reference:
/// 7.3.7 Short-term reference picture set syntax
/// 7.4.8 Short-term reference picture set semantics
/// </remarks>
private ShortTermRefPicSet ProcessShortTermRefPicSets(NalUnitBitstreamNavigator nav, SequenceParameterSet sps, uint stRpsIdx)
{
var result = new ShortTermRefPicSet();
if (stRpsIdx != 0)
{
result.inter_ref_pic_set_prediction_flag = nav.ReadBit(); //inter_ref_pic_set_prediction_flag u(1)
}
if (result.inter_ref_pic_set_prediction_flag)
{
if (stRpsIdx == sps.num_short_term_ref_pic_sets)
{
result.delta_idx_minus1 = nav.ReadNonNegativeExponentialGolombAsUInt32(); //delta_idx_minus1 ue(v)
}
result.delta_rps_sign = nav.ReadBit() ? (byte)1 : (byte)0; //delta_rps_sign u(1)
result.abs_delta_rps_minus1 = nav.ReadNonNegativeExponentialGolombAsUInt32(); //abs_delta_rps_minus1 ue(v)
// long deltaRps = (1 - 2 * delta_rps_sign) * (abs_delta_rps_minus1 + 1);
uint numDeltaPocs = CalculateNumDeltaPictureOrderCounts(sps.ShortTermRefPicSets, stRpsIdx, result);
for (int j = 0; j <= numDeltaPocs; j++)
{
result.used_by_curr_pic_flag.Add(nav.ReadBit()); //used_by_curr_pic_flag[ j ] u(1)
if (!result.used_by_curr_pic_flag[j])
{
result.use_delta_flag.Add(nav.ReadBit()); //use_delta_flag[ j ] u(1)
}
}
}
else
{
result.num_negative_pics = nav.ReadNonNegativeExponentialGolombAsUInt32(); //num_negative_pics ue(v)
result.num_positive_pics = nav.ReadNonNegativeExponentialGolombAsUInt32(); //num_positive_pics ue(v)
if (result.num_negative_pics > sps.sps_max_dec_pic_buffering_minus1[sps.sps_max_sub_layers_minus1])
{
System.Console.WriteLine("ShortTermRefPicSet.num_negative_pics > sps_max_dec_pic_buffering_minus1");
return(result);
}
if (result.num_positive_pics > sps.sps_max_dec_pic_buffering_minus1[sps.sps_max_sub_layers_minus1])
{
System.Console.WriteLine("ShortTermRefPicSet.num_positive_pics > sps_max_dec_pic_buffering_minus1");
return(result);
}
for (int i = 0; i < result.num_negative_pics; i++)
{
result.delta_poc_s0_minus1.Add(nav.ReadNonNegativeExponentialGolombAsUInt32()); //delta_poc_s0_minus1[ i ] ue(v)
result.used_by_curr_pic_s0_flag.Add(nav.ReadBit()); //used_by_curr_pic_s0_flag[ i ] u(1)
}
for (int i = 0; i < result.num_positive_pics; i++)
{
result.delta_poc_s1_minus1.Add(nav.ReadNonNegativeExponentialGolombAsUInt32()); //delta_poc_s1_minus1[ i ] ue(v)
result.used_by_curr_pic_s1_flag.Add(nav.ReadBit()); //used_by_curr_pic_s1_flag[ i ] u(1)
}
}
return(result);
}