/* * MPEG 1.0/2.0/2.5 audio layer I, II, III decoding with libmpg123 * * Copyright (C) 2010-2013 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.h" #include "mpvcore/mp_msg.h" #include #if (defined MPG123_API_VERSION) && (MPG123_API_VERSION < 33) #error "This should not happen" #endif struct ad_mpg123_context { mpg123_handle *handle; char new_format; /* Running mean for bit rate, stream length estimation. */ float mean_rate; unsigned int mean_count; /* Time delay for updates. */ short delay; /* 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; 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; /* 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. * If wanting a specific encoding here, configure format matrix and * make sure it is in set_format(). */ /* 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) */ /* 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.); 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]); } /* libmpg123 has a new format ready; query and store, return return value of mpg123_getformat() */ static int set_format(sh_audio_t *sh, struct ad_mpg123_context *con) { int ret; long rate; int channels; int encoding; ret = mpg123_getformat(con->handle, &rate, &channels, &encoding); if(ret == MPG123_OK) { mp_chmap_from_channels(&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; break; case MPG123_ENC_SIGNED_16: sh->sample_format = AF_FORMAT_S16_NE; 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; break; case 0x200: /* MPG123_ENC_FLOAT_32 */ sh->sample_format = AF_FORMAT_FLOAT_NE; break; default: /* This means we got a funny custom build of libmpg123 that only supports an unknown format. */ mp_msg(MSGT_DECAUDIO, MSGL_ERR, "Bad encoding from mpg123: %i.\n", encoding); return MPG123_ERR; } /* 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 * (af_fmt2bits(sh->sample_format) / 8); con->new_format = 0; } return ret; } /* 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; /* Fetch new format now, after old data has been used. */ if(con->new_format) ret = set_format(sh, con); /* Feed the decoder. This will only fire from the second round on. */ if (ret == MPG123_NEED_MORE) { /* Feed more input data. */ struct demux_packet *pkt = demux_read_packet(sh->gsh); if (!pkt) break; /* Apparently that's it. EOF. */ /* Next bytes from that presentation time. */ if (pkt->pts != MP_NOPTS_VALUE) { sh->pts = pkt->pts; sh->pts_bytes = 0; } /* Have to use mpg123_feed() to avoid decoding here. */ ret = mpg123_feed(con->handle, pkt->buffer, pkt->len); talloc_free(pkt); if (ret == MPG123_ERR) break; /* Indication of format change is possible here (from mpg123_decode()). */ if(ret == MPG123_NEW_FORMAT) { con->new_format = 1; if(got) break; /* Do not switch format during a chunk. */ ret = set_format(sh, con); } } /* 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. */ if (!buf) { /* fake call just for feeding to get format */ ret = set_format(sh, con); } 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); } got += got_now; sh->pts_bytes += got_now; /* Indication of format change should happen here. */ if(ret == MPG123_NEW_FORMAT) { con->new_format = 1; if(got) break; /* Do not switch format during a chunk. */ ret = set_format(sh, con); } } while (ret == MPG123_NEED_MORE || (got == 0 && count != 0)); if (ret == MPG123_ERR) { mp_msg(MSGT_DECAUDIO, MSGL_ERR, "mpg123 decoding failed: %s\n", mpg123_strerror(con->handle)); } 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) && set_format(sh, con) == MPG123_OK) { /* format setting again just for return value */ return 1; } else { mp_msg(MSGT_DECAUDIO, MSGL_ERR, "mpg123 failed to reopen stream: %s\n", mpg123_strerror(con->handle)); return 0; } } /* Now we really start accessing some data and determining file format. * Format now is allowed to change on-the-fly. Here is the only point * that has MPlayer react to errors. We have to pray that exceptional * erros in other places simply cannot occur. */ static int init(sh_audio_t *sh, const char *decoder) { mpg123_id3v2 *v2; struct mpg123_frameinfo finfo; struct ad_mpg123_context *con = sh->context; con->new_format = 0; if (reopen_stream(sh) && /* 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; con->delay = 1; con->mean_rate = 0.; con->mean_count = 0; con->vbr = (finfo.vbr != MPG123_CBR); return 1; } else { mp_msg(MSGT_DECAUDIO, MSGL_ERR, "mpg123 init error: %s\n", mpg123_strerror(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(); } /* 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; } } } static int decode_audio(sh_audio_t *sh, unsigned char *buf, int minlen, int maxlen) { int bytes; bytes = decode_a_bit(sh, buf, maxlen); /* This EOF is ignored, apparently, until input data is exhausted. */ if (bytes == 0) return -1; /* EOF */ update_info(sh); 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)) { update_info(sh); 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; } static void add_decoders(struct mp_decoder_list *list) { mp_add_decoder(list, "mpg123", "mp3", "mp3", "High-performance decoder using libmpg123"); } const struct ad_functions ad_mpg123 = { .name = "mpg123", .add_decoders = add_decoders, .preinit = preinit, .init = init, .uninit = uninit, .control = control, .decode_audio = decode_audio, };