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mpv/audio/decode/ad_mpg123.c

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/*
* MPEG 1.0/2.0/2.5 audio layer I, II, III decoding with libmpg123
*
* Copyright (C) 2010-2012 Thomas Orgis <thomas@orgis.org>
*
* 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 <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include "config.h"
#include "ad_internal.h"
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 <mpg123.h>
/* 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, const char *decoder)
{
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);
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;
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;
}
static void add_decoders(struct mp_decoder_list *list)
{
mp_add_decoder(list, "mpg123", "mp3", "mp3",
"High-performance decoder using libmpg123");
}
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