/* * MPEG 1.0/2.0/2.5 audio layer I, II, III decoding with libmpg123 * * Copyright (C) 2010-2012 Thomas Orgis * * MPlayer is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * MPlayer is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License along * with MPlayer; if not, write to the Free Software Foundation, Inc., * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. */ #include #include #include #include "config.h" #include "ad_internal.h" static const ad_info_t info = { "MPEG 1.0/2.0/2.5 layers I, II, III", "mpg123", "Thomas Orgis", "mpg123.org", "High-performance decoder using libmpg123." }; LIBAD_EXTERN(mpg123) /* Reducing the ifdeffery to two main variants: * 1. most compatible to any libmpg123 version * 2. fastest variant with recent libmpg123 (>=1.14) * Running variant 2 on older libmpg123 versions may work in * principle, but is not supported. * So, please leave the check for MPG123_API_VERSION there, m-kay? */ #include /* Enable faster mode of operation with newer libmpg123, avoiding * unnecessary memcpy() calls. */ #if (defined MPG123_API_VERSION) && (MPG123_API_VERSION >= 33) #define AD_MPG123_FRAMEWISE #endif /* Switch for updating bitrate info of VBR files. Not essential. */ #define AD_MPG123_MEAN_BITRATE /* Funny thing, that. I assume I shall use it for selecting mpg123 channels. * Please correct me if I guessed wrong. */ extern int fakemono; struct ad_mpg123_context { mpg123_handle *handle; #ifdef AD_MPG123_MEAN_BITRATE /* Running mean for bit rate, stream length estimation. */ float mean_rate; unsigned int mean_count; /* Time delay for updates. */ short delay; #endif /* If the stream is actually VBR. */ char vbr; }; /* This initializes libmpg123 and prepares the handle, including funky * parameters. */ static int preinit(sh_audio_t *sh) { int err, flag; struct ad_mpg123_context *con; /* Assumption: You always call preinit + init + uninit, on every file. * But you stop at preinit in case it fails. * If that is not true, one must ensure not to call mpg123_init / exit * twice in a row. */ if (mpg123_init() != MPG123_OK) return 0; sh->context = malloc(sizeof(struct ad_mpg123_context)); con = sh->context; /* Auto-choice of optimized decoder (first argument NULL). */ con->handle = mpg123_new(NULL, &err); if (!con->handle) goto bad_end; /* Guessing here: Default value triggers forced upmix of mono to stereo. */ flag = fakemono == 0 ? MPG123_FORCE_STEREO : fakemono == 1 ? MPG123_MONO_LEFT : fakemono == 2 ? MPG123_MONO_RIGHT : 0; if (mpg123_param(con->handle, MPG123_ADD_FLAGS, flag, 0.0) != MPG123_OK) goto bad_end; /* Basic settings. * Don't spill messages, enable better resync with non-seekable streams. * Give both flags individually without error checking to keep going with * old libmpg123. Generally, it is not fatal if the flags are not * honored */ mpg123_param(con->handle, MPG123_ADD_FLAGS, MPG123_QUIET, 0.0); /* Do not bail out on malformed streams at all. * MPlayer does not handle a decoder throwing the towel on crappy input. */ mpg123_param(con->handle, MPG123_RESYNC_LIMIT, -1, 0.0); /* Open decisions: Configure libmpg123 to force encoding (or stay open about * library builds that support only float or int32 output), (de)configure * gapless decoding (won't work with seeking in MPlayer, though). * Don't forget to eventually enable ReplayGain/RVA support, too. * Let's try to run with the default for now. */ /* That would produce floating point output. * You can get 32 and 24 bit ints, even 8 bit via format matrix. */ /* mpg123_param(con->handle, MPG123_ADD_FLAGS, MPG123_FORCE_FLOAT, 0.); */ /* Example for RVA choice (available since libmpg123 1.0.0): mpg123_param(con->handle, MPG123_RVA, MPG123_RVA_MIX, 0.0) */ #ifdef AD_MPG123_FRAMEWISE /* Prevent funky automatic resampling. * This way, we can be sure that one frame will never produce * more than 1152 stereo samples. */ mpg123_param(con->handle, MPG123_REMOVE_FLAGS, MPG123_AUTO_RESAMPLE, 0.); #else /* Older mpg123 is vulnerable to concatenated streams when gapless cutting * is enabled (will only play the jingle of a badly constructed radio * stream). The versions using framewise decoding are fine with that. */ mpg123_param(con->handle, MPG123_REMOVE_FLAGS, MPG123_GAPLESS, 0.); #endif return 1; bad_end: if (!con->handle) mp_msg(MSGT_DECAUDIO, MSGL_ERR, "mpg123 preinit error: %s\n", mpg123_plain_strerror(err)); else mp_msg(MSGT_DECAUDIO, MSGL_ERR, "mpg123 preinit error: %s\n", mpg123_strerror(con->handle)); if (con->handle) mpg123_delete(con->handle); mpg123_exit(); free(sh->context); sh->context = NULL; return 0; } /* Compute bitrate from frame size. */ static int compute_bitrate(struct mpg123_frameinfo *i) { static const int samples_per_frame[4][4] = { {-1, 384, 1152, 1152}, /* MPEG 1 */ {-1, 384, 1152, 576}, /* MPEG 2 */ {-1, 384, 1152, 576}, /* MPEG 2.5 */ {-1, -1, -1, -1}, /* Unknown */ }; return (int) ((i->framesize + 4) * 8 * i->rate * 0.001 / samples_per_frame[i->version][i->layer] + 0.5); } /* Opted against the header printout from old mp3lib, too much * irrelevant info. This is modelled after the mpg123 app's * standard output line. * If more verbosity is demanded, one can add more detail and * also throw in ID3v2 info which libmpg123 collects anyway. */ static void print_header_compact(struct mpg123_frameinfo *i) { static const char *smodes[5] = { "stereo", "joint-stereo", "dual-channel", "mono", "invalid" }; static const char *layers[4] = { "Unknown", "I", "II", "III" }; static const char *versions[4] = { "1.0", "2.0", "2.5", "x.x" }; mp_msg(MSGT_DECAUDIO, MSGL_V, "MPEG %s layer %s, ", versions[i->version], layers[i->layer]); switch (i->vbr) { case MPG123_CBR: if (i->bitrate) mp_msg(MSGT_DECAUDIO, MSGL_V, "%d kbit/s", i->bitrate); else mp_msg(MSGT_DECAUDIO, MSGL_V, "%d kbit/s (free format)", compute_bitrate(i)); break; case MPG123_VBR: mp_msg(MSGT_DECAUDIO, MSGL_V, "VBR"); break; case MPG123_ABR: mp_msg(MSGT_DECAUDIO, MSGL_V, "%d kbit/s ABR", i->abr_rate); break; default: mp_msg(MSGT_DECAUDIO, MSGL_V, "???"); } mp_msg(MSGT_DECAUDIO, MSGL_V, ", %ld Hz %s\n", i->rate, smodes[i->mode]); } /* This tries to extract a requested amount of decoded data. * Even when you request 0 bytes, it will feed enough input so that * the decoder _could_ have delivered something. * Returns byte count >= 0, -1 on error. * * Thoughts on exact pts keeping: * We have to assume that MPEG frames are cut in pieces by packet boundaries. * Also, it might be possible that the first packet does not contain enough * data to ensure initial stream sync... or re-sync on erroneous streams. * So we need something robust to relate the decoded byte count to the correct * time stamp. This is tricky, though. From the outside, you cannot tell if, * after having fed two packets until the first output arrives, one should * start counting from the first packet's pts or the second packet's. * So, let's just count from the last fed package's pts. If the packets are * exactly cut to MPEG frames, this will cause one frame mismatch in the * beginning (when mpg123 peeks ahead for the following header), but will * be corrected with the third frame already. One might add special code to * not increment the base pts past the first packet's after a resync before * the first decoded bytes arrived. */ static int decode_a_bit(sh_audio_t *sh, unsigned char *buf, int count) { int ret = MPG123_OK; int got = 0; struct ad_mpg123_context *con = sh->context; /* There will be one MPG123_NEW_FORMAT message on first open. * This will be handled in init(). */ do { size_t got_now = 0; /* Feed the decoder. This will only fire from the second round on. */ if (ret == MPG123_NEED_MORE) { int incount; double pts; unsigned char *inbuf; /* Feed more input data. */ incount = ds_get_packet_pts(sh->ds, &inbuf, &pts); if (incount <= 0) break; /* Apparently that's it. EOF. */ /* Next bytes from that presentation time. */ if (pts != MP_NOPTS_VALUE) { sh->pts = pts; sh->pts_bytes = 0; } #ifdef AD_MPG123_FRAMEWISE /* Have to use mpg123_feed() to avoid decoding here. */ ret = mpg123_feed(con->handle, inbuf, incount); #else /* Do not use mpg123_feed(), added in later libmpg123 versions. */ ret = mpg123_decode(con->handle, inbuf, incount, NULL, 0, NULL); #endif if (ret == MPG123_ERR) break; } /* Theoretically, mpg123 could return MPG123_DONE, so be prepared. * Should not happen in our usage, but it is a valid return code. */ else if (ret == MPG123_ERR || ret == MPG123_DONE) break; /* Try to decode a bit. This is the return value that counts * for the loop condition. */ #ifdef AD_MPG123_FRAMEWISE if (!buf) { /* fake call just for feeding to get format */ ret = mpg123_getformat(con->handle, NULL, NULL, NULL); } else { /* This is the decoding. One frame at a time. */ ret = mpg123_replace_buffer(con->handle, buf, count); if (ret == MPG123_OK) ret = mpg123_decode_frame(con->handle, NULL, NULL, &got_now); } #else ret = mpg123_decode(con->handle, NULL, 0, buf + got, count - got, &got_now); #endif got += got_now; sh->pts_bytes += got_now; #ifdef AD_MPG123_FRAMEWISE } while (ret == MPG123_NEED_MORE || (got == 0 && count != 0)); #else } while (ret == MPG123_NEED_MORE || got < count); #endif if (ret == MPG123_ERR) { mp_msg(MSGT_DECAUDIO, MSGL_ERR, "mpg123 decoding failed: %s\n", mpg123_strerror(con->handle)); mpg123_close(con->handle); return -1; } return got; } /* Close, reopen stream. Feed data until we know the format of the stream. * 1 on success, 0 on error */ static int reopen_stream(sh_audio_t *sh) { struct ad_mpg123_context *con = (struct ad_mpg123_context*) sh->context; mpg123_close(con->handle); /* No resetting of the context: * We do not want to loose the mean bitrate data. */ /* Open and make sure we have fed enough data to get stream properties. */ if (MPG123_OK == mpg123_open_feed(con->handle) && /* Feed data until mpg123 is ready (has found stream beginning). */ !decode_a_bit(sh, NULL, 0)) { return 1; } else { mp_msg(MSGT_DECAUDIO, MSGL_ERR, "mpg123 failed to reopen stream: %s\n", mpg123_strerror(con->handle)); mpg123_close(con->handle); return 0; } } /* Now we really start accessing some data and determining file format. * Paranoia note: The mpg123_close() on errors is not really necessary, * But it ensures that we don't accidentally continue decoding with a * bad state (possibly interpreting the format badly or whatnot). */ static int init(sh_audio_t *sh) { long rate = 0; int channels = 0; int encoding = 0; mpg123_id3v2 *v2; struct mpg123_frameinfo finfo; struct ad_mpg123_context *con = sh->context; /* We're open about any output format that libmpg123 will suggest. * Note that a standard build will always default to 16 bit signed and * the native sample rate of the file. */ if (MPG123_OK == mpg123_format_all(con->handle) && reopen_stream(sh) && MPG123_OK == mpg123_getformat(con->handle, &rate, &channels, &encoding) && /* Forbid the format to change later on. */ MPG123_OK == mpg123_format_none(con->handle) && MPG123_OK == mpg123_format(con->handle, rate, channels, encoding) && /* Get MPEG header info. */ MPG123_OK == mpg123_info(con->handle, &finfo) && /* Since we queried format, mpg123 should have read past ID3v2 tags. * We need to decide if printing of UTF-8 encoded text info is wanted. */ MPG123_OK == mpg123_id3(con->handle, NULL, &v2)) { /* If we are here, we passed all hurdles. Yay! Extract the info. */ print_header_compact(&finfo); /* Do we want to print out the UTF-8 Id3v2 info? if (v2) print_id3v2(v2); */ /* Have kb/s, want B/s * For VBR, the first frame will be a bad estimate. */ sh->i_bps = (finfo.bitrate ? finfo.bitrate : compute_bitrate(&finfo)) * 1000 / 8; #ifdef AD_MPG123_MEAN_BITRATE con->delay = 1; con->mean_rate = 0.; con->mean_count = 0; #endif con->vbr = (finfo.vbr != MPG123_CBR); sh->channels = channels; sh->samplerate = rate; /* Without external force, mpg123 will always choose signed encoding, * and non-16-bit only on builds that don't support it. * Be reminded that it doesn't matter to the MPEG file what encoding * is produced from it. */ switch (encoding) { case MPG123_ENC_SIGNED_8: sh->sample_format = AF_FORMAT_S8; sh->samplesize = 1; break; case MPG123_ENC_SIGNED_16: sh->sample_format = AF_FORMAT_S16_NE; sh->samplesize = 2; break; /* To stay compatible with the oldest libmpg123 headers, do not rely * on float and 32 bit encoding symbols being defined. * Those formats came later */ case 0x1180: /* MPG123_ENC_SIGNED_32 */ sh->sample_format = AF_FORMAT_S32_NE; sh->samplesize = 4; break; case 0x200: /* MPG123_ENC_FLOAT_32 */ sh->sample_format = AF_FORMAT_FLOAT_NE; sh->samplesize = 4; break; default: mp_msg(MSGT_DECAUDIO, MSGL_ERR, "Bad encoding from mpg123: %i.\n", encoding); mpg123_close(con->handle); return 0; } #ifdef AD_MPG123_FRAMEWISE /* Going to decode directly to MPlayer's memory. It is important * to have MPG123_AUTO_RESAMPLE disabled for the buffer size * being an all-time limit. */ sh->audio_out_minsize = 1152 * 2 * sh->samplesize; #endif return 1; } else { mp_msg(MSGT_DECAUDIO, MSGL_ERR, "mpg123 init error: %s\n", mpg123_strerror(con->handle)); mpg123_close(con->handle); return 0; } } static void uninit(sh_audio_t *sh) { struct ad_mpg123_context *con = (struct ad_mpg123_context*) sh->context; mpg123_close(con->handle); mpg123_delete(con->handle); free(sh->context); sh->context = NULL; mpg123_exit(); } #ifdef AD_MPG123_MEAN_BITRATE /* Update mean bitrate. This could be dropped if accurate time display * on audio file playback is not desired. */ static void update_info(sh_audio_t *sh) { struct ad_mpg123_context *con = sh->context; if (con->vbr && --con->delay < 1) { struct mpg123_frameinfo finfo; if (MPG123_OK == mpg123_info(con->handle, &finfo)) { if (++con->mean_count > ((unsigned int) -1) / 2) con->mean_count = ((unsigned int) -1) / 4; /* Might not be numerically optimal, but works fine enough. */ con->mean_rate = ((con->mean_count - 1) * con->mean_rate + finfo.bitrate) / con->mean_count; sh->i_bps = (int) (con->mean_rate * 1000 / 8); con->delay = 10; } } } #endif static int decode_audio(sh_audio_t *sh, unsigned char *buf, int minlen, int maxlen) { int bytes; bytes = decode_a_bit(sh, buf, maxlen); if (bytes == 0) return -1; /* EOF */ #ifdef AD_MPG123_MEAN_BITRATE update_info(sh); #endif return bytes; } static int control(sh_audio_t *sh, int cmd, void *arg, ...) { switch (cmd) { case ADCTRL_RESYNC_STREAM: /* Close/reopen the stream for mpg123 to make sure it doesn't * think that it still knows the exact stream position. * Otherwise, we would have funny effects from the gapless code. * Oh, and it helps to minimize artifacts from jumping in the stream. */ if (reopen_stream(sh)) { #ifdef AD_MPG123_MEAN_BITRATE update_info(sh); #endif return CONTROL_TRUE; } else { /* MPlayer ignores this case! It just keeps on decoding. * So we have to make sure resync never fails ... */ mp_msg(MSGT_DECAUDIO, MSGL_ERR, "mpg123 cannot reopen stream for resync.\n"); return CONTROL_FALSE; } break; } return CONTROL_UNKNOWN; }