On Wed, Jan 24, 2024 at 1:58 AM Andrew Randrianasulu <randrianas...@gmail.com> wrote: > > So, I was having a blast hacking old en/decoder. > > My own hacks do not work on 64-bit yet (they run, just sounds wrongs > :) ) but this one was tested on aarch64 Termux install, so should be > better > > https://github.com/Randrianasulu/iso-dist10 > > note: pcm2aiff too was not working for me, but mc (multichannel) and > lsf (low sampling frequency) mpeg de/encoders were good .. > > I wonder if mplex already can mux those streams? In man I see
Even if svn log says nothing will ever be done for SVCD multichannel I think it was working at some point? https://encode2mpeg.sourceforge.net/html/multichannel.html uses mplex? First time I saw bash script in 100s kb size range ... and for Windows https://web.archive.org/web/20051230022557/http://hypercubemx.free.fr/html/how_to_make_5_1__svcd.html I tried their software under wine - um, something was eating cpu time - so 3 min of 6 ch. audio was encoding at 1/10 of realtime - for 30+ minutes! mctoolame on the other hand encodes same file in 190-75 seconds depend on -ffast-math usage. I was surprized that 'threshold" calculations in psycho_1.c (psychoacoustical model one) eat up to half of cpu time! So adding supposedly faster fftw from twolame not changed speed as radically as I hoped. ==== opreport log ==== samples cum. samples % cum. % image name symbol name 579112 579112 50.5768 50.5768 mctoolame threshold 115666 694778 10.1017 60.6785 mctoolame psycho_1 101489 796267 8.8636 69.5421 mctoolame II_a_bit_allocation 53317 849584 4.6564 74.1985 mctoolame noise_label 43665 893249 3.8135 78.0120 mctoolame window_subband 33099 926348 2.8907 80.9027 mctoolame filter_subband 28008 954356 2.4461 83.3488 mctoolame fht 24048 978404 2.1002 85.4490 mctoolame transmission_channel 20451 998855 1.7861 87.2351 mctoolame II_subband_quantization_mc 15968 1014823 1.3946 88.6297 mctoolame matricing_fft 15814 1030637 1.3811 90.0108 mctoolame II_scale_factor_calc 14554 1045191 1.2711 91.2819 mctoolame tc_alloc 14359 1059550 1.2540 92.5359 mctoolame lfe_filter 13910 1073460 1.2148 93.7507 mctoolame II_tonal_label 12842 1086302 1.1216 94.8723 mctoolame II_subband_quantization 6381 1092683 0.5573 95.4296 mctoolame putbits 6330 1099013 0.5528 95.9824 libc-2.33.so fwrite 5476 1104489 0.4782 96.4607 mctoolame II_smr 4562 1109051 0.3984 96.8591 mctoolame get_audio 3760 1112811 0.3284 97.1875 mctoolame II_sample_encoding_mc 3261 1116072 0.2848 97.4723 libc-2.33.so _IO_file_xsputn@@GLIBC_2.1 2587 1118659 0.2259 97.6982 mctoolame II_sample_encoding 2053 1120712 0.1793 97.8775 mctoolame normalizing 1906 1122618 0.1665 98.0440 mctoolame matricing 1723 1124341 0.1505 98.1944 mctoolame II_transmission_pattern 1628 1125969 0.1422 98.3366 mctoolame psycho_1_fft 1491 1127460 0.1302 98.4668 mctoolame II_minimum_mask 1273 1128733 0.1112 98.5780 mctoolame II_CRC_calc_mc 1234 1129967 0.1078 98.6858 mctoolame create_dct_matrix 964 1130931 0.0842 98.7700 mctoolame II_encode_scale 880 1131811 0.0769 98.8468 mctoolame main 821 1132632 0.0717 98.9185 mctoolame II_main_bit_allocation 781 1133413 0.0682 98.9867 kallsyms tick_do_update_jiffies64 742 1134155 0.0648 99.0515 mctoolame update_CRC 689 1134844 0.0602 99.1117 kallsyms copy_user_generic_string [rest is skipped] from 13818-3.pdf I currently read: ==== quote === The ISO/MPEG-Audio Multichannel system provides full compatibility with the ISO Standard 11172-3. This compatibility is realised by coding the basic stereo information in conformance with ISO/IEC 11172-3 and exploiting the ancillary data field of the ISO/IEC 11172-3 audio frame and an optional extension bit stream for the multichannel extension. The complete ISO/IEC 11172-3 frame incorporates four different types of information: - Header information within the first 32 bits of the ISO/IEC 11172-3 audio frame. - Cyclic Redundancy Check (CRC), consisting of 16 bits, just after the header information (optional). - Audio data, for Layer II consisting of bit allocation (BAL), scalefactor select information (SCFSI), scalefactors (SCF), and the subband samples. - Ancillary data. Due to the large number of different applications which will use the ISO/IEC 11172-3 Standard, the length and usage of this field are not specified. The variable length of the ancillary data field enables packing the complete extension information of the channels T2/T3/T4 into the first part of the ancillary data field. If the MC encoder does not use all of the ancillary data field for the multichannel extension information, the remaining part of the field can be used for other ancillary data. The bit rate required for the multichannel extension information may vary on a frame by frame basis, depending on the sound signals. The overall bit rate may be increased above that provided for in ISO/IEC 11172-3 by the use of an optional extension bit stream. The maximum bit rate, including the extension bit stream, is given by the following table: Sampling Frequency Layer Maximum Total Bit Rate 32 kHz I 903 kbit/s 32 kHz II 839 kbit/s 32 kHz III 775 kbit/s 44.1 kHz I 1075 kbit/s 44.1 kHz II 1011 kbit/s 44.1 kHz III 947 kbit/s 48 kHz I 1130 kbit/s 48 kHz II 1066 kbit/s 48 kHz III 1002 kbit/s huh, quite big - for all those channels ... ===== thing is, this extension bitstream just dumped by encoder as file, and I have currently no idea how to incorporate it back into mpeg stream :) Anyway, if specified bitrate not above 384 Kbit/s older standart used, so current mplex IMO muxes it correctly - I can extract mp2 audio with ffmpeg and decode it back in 5.1 sound ... additionally, I found two typos in man and comments :) patch attached > > BUGS > The multiplexer should handle MPEG(5.1) audio. > > but date on man page from 2001 ...
Index: docs/mp2enc.1 =================================================================== --- docs/mp2enc.1 (revision 3509) +++ docs/mp2enc.1 (working copy) @@ -31,7 +31,7 @@ Mp2enc is a simple MPEG-1 layer-I/II audio encoder. It is actually a very mildly warmed over version of the MPEG Software Simulation Group's reference encoder. It accepts a WAV file or stream on stdin and -ouputs an a layer-I/II elementary audio stream. It is included in the +outputs an a layer-I/II elementary audio stream. It is included in the \fBmjpegtools\fP(1) primarily for reasons of completeness and because it is able to perform sampling rate conversion. .PP Index: mplex/systems.cpp =================================================================== --- mplex/systems.cpp (revision 3509) +++ mplex/systems.cpp (working copy) @@ -261,9 +261,9 @@ /************************ * * Is this a stream where for the MPEG-2 - * header extensionsappear? + * header extensions appear? * - * The version below is correct at least forDVD + * The version below is correct at least for DVD * authoring. The function is virtual in case sometime * someplace a different format where PRIVATE_STR_2 is used * differently is encountered.
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