private static unsafe void patch_slice_header(h264_sps_id_patcher_t h, bit_reader_t bs, bs_t bd)
{
uint first_mb_in_slice = (uint)ue_bits(bs);
uint slice_type = (uint)ue_bits(bs);
uint pps_id = (uint)ue_bits(bs);
pps_id = (uint)h.map_pps[pps_id];
Debug.Assert(pps_id <= 255);
h264e_bs_put_golomb(bd, first_mb_in_slice);
h264e_bs_put_golomb(bd, slice_type);
h264e_bs_put_golomb(bd, pps_id);
copy_bits(bs, bd);
}
private static unsafe int patch_pps(h264_sps_id_patcher_t h, bit_reader_t bs, bs_t bd, int new_pps_id,
int *old_id)
{
int bytes;
uint pps_id = (uint)ue_bits(bs); // max = 255
uint sps_id = (uint)ue_bits(bs); // max = 31
*old_id = (int)pps_id;
sps_id = (uint)h.map_sps[sps_id];
pps_id = (uint)new_pps_id;
Debug.Assert(sps_id <= 31);
Debug.Assert(pps_id <= 255);
h264e_bs_put_golomb(bd, pps_id);
h264e_bs_put_golomb(bd, sps_id);
copy_bits(bs, bd);
bytes = (int)h264e_bs_byte_align(bd) / 8;
h264e_bs_flush(bd);
return(bytes);
}
private static unsafe int transcode_nalu(h264_sps_id_patcher_t h, byte *src, int nalu_bytes, byte *dst)
{
int old_id;
bit_reader_t bst = new bit_reader_t();
bs_t bdt = new bs_t();
bit_reader_t bs = new bit_reader_t();
bs_t bd = new bs_t();
int payload_type = src[0] & 31;
*dst = *src;
h264e_bs_init_bits(bd, dst + 1);
init_bits(bs, src + 1, (uint)nalu_bytes - 1);
h264e_bs_init_bits(bdt, dst + 1);
init_bits(bst, src + 1, (uint)nalu_bytes - 1);
switch (payload_type)
{
case 7:
{
int cb = change_sps_id(bst, bdt, 0, &old_id);
int id = find_mem_cache(h.sps_cache, h.sps_bytes, MINIMP4_MAX_SPS, dst + 1, cb);
if (id == -1)
{
return(0);
}
h.map_sps[old_id] = id;
change_sps_id(bs, bd, id, &old_id);
}
break;
case 8:
{
int cb = patch_pps(h, bst, bdt, 0, &old_id);
int id = find_mem_cache(h.pps_cache, h.pps_bytes, MINIMP4_MAX_PPS, dst + 1, cb);
if (id == -1)
{
return(0);
}
h.map_pps[old_id] = id;
patch_pps(h, bs, bd, id, &old_id);
}
break;
case 1:
case 2:
case 5:
patch_slice_header(h, bs, bd);
break;
default:
memcpy(dst, src, nalu_bytes);
return(nalu_bytes);
}
nalu_bytes = (int)(1 + h264e_bs_byte_align(bd) / 8);
h264e_bs_flush(bd);
return(nalu_bytes);
}
