search for: qlp_coeff_precision

...hould the latter ignore that? > > We can only speculate about this, but I think this code has been duplicated > by accident, and therefore it wasn't changed as the code shouldn't have > been there in the first place. Well, the code in process_subframe_() calculates MAX value of qlp_coeff_precision, while the code in evaluate_lpc_subframe_() adjusts CURRENT qlp_coeff_precision. It's possible to move the logic from evaluate_lpc_subframe_() into process_subframe_(), see the attached patch, but I'm not sure that the code becomes much clearer after it. -------------- next part ----------...

Martijn van Beurden wrote: > Yes, but that MAX value is used to loop over the > qlp_coeff_precision values between MIN and MAX. So, if the > qlp_coeff_precision value is limited in the loop but MAX is not > limited, the loop does the exact same thing multiple times: a > waste of time. Therefore, only the MAX should be limited. > > I don't think the logic is needed directly afte...

...cl wrote: > BTW, what can you say about the following place in stream_decoder.c > in read_subframe_lpc_() function: > > /*@@@@@@ technically not pessimistic enough, should be more like > if( (FLAC__uint64)order * ((((FLAC__uint64)1)<<bps)-1) * ((1<<subframe->qlp_coeff_precision)-1) < (((FLAC__uint64)-1) << 32) ) > */ > if(bps + subframe->qlp_coeff_precision + FLAC__bitmath_ilog2(order) <= 32) > > Is it really "not pessimistic enough"? Can it be changed similarly to your patch > for stream_encoder.c? Good question. I'...

On Thu, Jun 19, 2014 at 06:25:57PM +0400, lvqcl wrote: > Now I wonder why evaluate_lpc_subframe_() function in stream_encoder.c contains > almost the same code, but without any comments that it's not enough pessimistic: > evaluate_lpc_subframe_(): > > if(subframe_bps + qlp_coeff_precision + FLAC__bitmath_ilog2(order) <= 32) > if(subframe_bps <= 16 && qlp_coeff_precision <= 16) > encoder->private_->local_lpc_compute_residual_from_qlp_coefficients_16bit(...); > else > encoder->private_->local_lpc_compute_residual_from_qlp_coefficients(......

I don't understand the comment in src/libFLAC/stream_decoder.c: /*@@@@@@ technically not pessimistic enough, should be more like if( (FLAC__uint64)order * ((((FLAC__uint64)1)<<bps)-1) * ((1<<subframe->qlp_coeff_precision)-1) < (((FLAC__uint64)-1) << 32) ) */ if(bps + subframe->qlp_coeff_precision + FLAC__bitmath_ilog2(order) <= 32) see http://git.xiph.org/?p=flac.git;a=commitdiff;h=8534bbe4e92300609fd6dc289d882130b69d48cd First, I suspect that there's a typo and the intended code is ....

...e "private/cpu.h" #include "private/crc.h" #include "private/fixed.h" @@ -1738,10 +1739,11 @@ /* decode the subframe */ memcpy(decoder->private_->output[channel], subframe->warmup, sizeof(FLAC__int32) * order); - if(bps <= 16 && subframe->qlp_coeff_precision <= 16) - decoder->private_->local_lpc_restore_signal_16bit(decoder->private_->residual[channel], decoder->private_->frame.header.blocksize-order, subframe->qlp_coeff, order, subframe->quantization_level, decoder->private_->output[channel]+order); - else if(bps + su...

...pposite direction but they were implemented directly with << >> and in C negative shifts are undefined. treat as an error for now to avoid bad behavior but I need to come back to this to specify exactly." But libFLAC itself doesn't care about their values. It checks a value of qlp_coeff_precision, though. So this patch adds a check of a value of quantization_level. I'm not sure what should libFLAC do if a negative (=invalid) value of quantization_level is encountered. But it seems logical that it should treat an invalid value of quantization_level in the same way as it treats an inval...

...f flac. This switch should enable exhaustive search for the optimal qlp coefficient precision, but the resulting files are usually 0.5% larger then when not using the switch. I stumbled upon this code in stream_encoder > if(encoder->protected_->do_qlp_coeff_prec_search) { > min_qlp_coeff_precision = FLAC__MIN_QLP_COEFF_PRECISION; > /* try to ensure a 32-bit datapath throughout for > 16bps(+1bps for side channel) or less */ > if(subframe_bps <= 17) { > max_qlp_coeff_precision = flac_min(32 - subframe_bps - > lpc_order, FLAC__MAX_QLP_COEFF_PRECISION); >...

On Mon, Apr 20, 2015 at 08:00:20PM +0300, lvqcl wrote: > I don't understand the comment in src/libFLAC/stream_decoder.c: > > /*@@@@@@ technically not pessimistic enough, should be more like > if( (FLAC__uint64)order * ((((FLAC__uint64)1)<<bps)-1) * ((1<<subframe->qlp_coeff_precision)-1) < (((FLAC__uint64)-1) << 32) ) > */ > if(bps + subframe->qlp_coeff_precision + FLAC__bitmath_ilog2(order) <= 32) > which is equivalent to the current > > bps + subframe->qlp_coeff_precision + FLAC__bitmath_ilog2(order) <= 32 > > So IMHO the comm...

In the precompute_partition_info_sums_ function, instead of selecting 64-bit accumulator when the signal bps is larger than 16, revert to the original approach based on partition size, but make room for few extra bits to not overflow with unusual signals where the average residual magnitude may be larger than bps. It slightly improves the performance with standard encoding levels and 16-bit files

...7 +682,7 @@ static FLAC__StreamEncoderInitStatus init_stream_internal_( if(encoder->protected_->bits_per_sample < 16) { /* @@@ need some data about how to set this here w.r.t. blocksize and sample rate */ /* @@@ until then we'll make a guess */ - encoder->protected_->qlp_coeff_precision = max(FLAC__MIN_QLP_COEFF_PRECISION, 2 + encoder->protected_->bits_per_sample / 2); + encoder->protected_->qlp_coeff_precision = flac_max(FLAC__MIN_QLP_COEFF_PRECISION, 2 + encoder->protected_->bits_per_sample / 2); } else if(encoder->protected_->bits_per_sample == 1...

...ream. I've checked my interpretation against "flac -a" and it seems to read 17 bits for each warmup sample. Here is its output: frame=168 blocksize=4608 sample_rate=44100 channels=2 channel_assignment=RIGHT_SIDE subframe=0 wasted_bits=0 type=LPC order=5 partition_order=4 qlp_coeff_precision=12 quantization_level=9 warmup[0]=-993 warmup[1]=-476 warmup[2]=171 warmup[3]=115 warmup[4]=-766 Tor =================================================================== EASY and FREE access to your email anywhere: http://Mailreader.com/ =============================================...

libFLAC limits the value of qlp_coeff_precision to make sure that 32-bit math is enough for decoding of 16-bit audio. subframe_bps can be equal to 17 for 16-bit input (for side channel). So the value of subframe_bps should be compared with 17, not 16 (see also http://git.xiph.org/?p=flac.git;a=blob;f=src/libFLAC/stream_encoder.c;hb=02591f6b4b0...

Martijn van Beurden wrote: > Yes, indeed. I removed the 17-bits part because I just matched > the code in evaluate_lpc_subframe_ with the process_subframe_ > code. It appears it only makes sense that those two pieces code > are the same. A bit of history: 1) The conditional "if(subframe_bps <= 16)" was added to evaluate_lpc_subframe_() in the commit

I think I've gotten FLAC__lpc_restore_signal() about as good as I'm going to get it. Here's what I have: -a new file, lpc_asm.s, which has the assembly routines -changes to cpu.h, cpu.c, and stream_decoder.c to enable them -changes to configure.in to support the new cpu stuff -a preliminary Makefile.am -maybe something else I'm forgetting Now automake complains that configure.in

...gt;private_->partitioned_rice_contents[channel], residual)) return false; break; default: *************** *** 1925,1936 **** /* decode the subframe */ memcpy(decoder->private_->output[channel], subframe->warmup, sizeof(FLAC__int32) * order); if(bps + subframe->qlp_coeff_precision + FLAC__bitmath_ilog2(order) <= 32) ! if(bps <= 16 && subframe->qlp_coeff_precision <= 16) ! decoder->private_->local_lpc_restore_signal_16bit(decoder->private_->residual[channel], decoder->private_->frame.header.blocksize-order, subframe->qlp_coeff, or...

...x400000000000d840 in init_encoder (lax=0, do_mid_side=0, loose_mid_side=0, do_exhaustive_model_search=0, do_escape_coding=0, do_qlp_coeff_prec_search=0, min_residual_partition_order=3, max_residual_partition_order=3, rice_parameter_search_dist=0, max_lpc_order=8, blocksize=4608, qlp_coeff_precision=0, channels=1, bps=16, sample_rate=44100, padding=0, requested_seek_points=0x60000000002ab138 "100x", num_requested_seek_points=-1, encoder_wrapper=0x80000fffffffa5c0) at encode.c:711 #6 0x2000000000123dc0 in stream_decoder_read_metadata_ ( decoder=0x60000000002b7d...

...6 "/home/mdz/english.wav", outfile=0x11ffffe3c "/home/mdz/english.flac", verbose=1, skip=0, verify=0, lax=0, do_mid_side=1, loose_mid_side=0, do_exhaustive_model_search=0, do_qlp_coeff_prec_search=0, rice_optimization_level=4, max_lpc_order=8, blocksize=4608, qlp_coeff_precision=0, padding=0) at encode.c:280 #7 0x12000a208 in main (argc=3, argv=0x11ffffc38) at main.c:293 and when decoding: #0 0x200000e7830 in FLAC__fixed_restore_signal (residual=0x1202ce480, data_len=4606, order=2, data=0x1202c9c78) at fixed.c:209 #1 0x200000ef25c in stream_decoder_read_subframe_...

.../tmp/test-9.flac", verbose=1, skip=0, verify=1, lax=0, do_mid_side=1, loose_mid_side=0, do_exhaustive_model_search=1, do_qlp_coeff_prec_search=1, min_residual_partition_order=0, max_residual_partition_order=16, rice_parameter_search_dist=0, max_lpc_order=32, blocksize=4608, qlp_coeff_precision=0, padding=0, requested_seek_points=0x8308120 "100x", num_requested_seek_points=-1) at encode.c:292 #13 0x8050aa4 in encode_file (infilename=0xbffffa09 "/tmp/test-9.wav", forced_outfilename=0xbfffe7d8 "/tmp/test-9.flac") at main.c:581 #14 0x804fd34 in mai...

..._encoder (lax=0, do_mid_side=0, > loose_mid_side=0, do_exhaustive_model_search=0, > do_escape_coding=0, > do_qlp_coeff_prec_search=0, min_residual_partition_order=3, > max_residual_partition_order=3, rice_parameter_search_dist=0, > max_lpc_order=8, blocksize=4608, qlp_coeff_precision=0, > channels=1, > bps=16, sample_rate=44100, padding=0, > requested_seek_points=0x60000000002ab138 "100x", > num_requested_seek_points=-1, encoder_wrapper=0x80000fffffffa5c0) > at encode.c:711 > #6 0x2000000000123dc0 in stream_decoder_read_metadata_...