mpv/audio/decode/ad_mpg123.c

302 lines
9.4 KiB
C

/*
* MPEG 1.0/2.0/2.5 audio layer I, II, III decoding with libmpg123
*
* Copyright (C) 2010-2013 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.h"
#include "common/msg.h"
#include <mpg123.h>
#if (defined MPG123_API_VERSION) && (MPG123_API_VERSION < 33)
#error "This should not happen"
#endif
struct ad_mpg123_context {
mpg123_handle *handle;
int sample_size;
/* 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;
};
static void uninit(struct dec_audio *da)
{
struct ad_mpg123_context *con = da->priv;
mpg123_close(con->handle);
mpg123_delete(con->handle);
mpg123_exit();
}
/* This initializes libmpg123 and prepares the handle, including funky
* parameters. */
static int init(struct dec_audio *da, const char *decoder)
{
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;
da->priv = talloc_zero(NULL, struct ad_mpg123_context);
con = da->priv;
/* 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.
* Background:
* Going to decode directly to the output buffer. It is important to have
* MPG123_AUTO_RESAMPLE disabled for the buffer size being an all-time
* limit.
* We need at least 1152 samples. dec_audio.c normally guarantees this. */
mpg123_param(con->handle, MPG123_REMOVE_FLAGS, MPG123_AUTO_RESAMPLE, 0.);
err = mpg123_open_feed(con->handle);
if (err != MPG123_OK)
goto bad_end;
return 1;
bad_end:
if (!con->handle) {
MP_ERR(da, "mpg123 preinit error: %s\n", mpg123_plain_strerror(err));
} else {
MP_ERR(da, "mpg123 preinit error: %s\n", mpg123_strerror(con->handle));
}
uninit(da);
return 0;
}
static int mpg123_format_to_af(int mpg123_encoding)
{
/* 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 (mpg123_encoding) {
case MPG123_ENC_SIGNED_8: return AF_FORMAT_S8;
case MPG123_ENC_SIGNED_16: return AF_FORMAT_S16;
case MPG123_ENC_SIGNED_32: return AF_FORMAT_S32;
case MPG123_ENC_FLOAT_32: return AF_FORMAT_FLOAT;
}
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 /
samples_per_frame[i->version][i->layer] + 0.5);
}
/* Update mean bitrate. This could be dropped if accurate time display
* on audio file playback is not desired. */
static void update_info(struct dec_audio *da)
{
struct ad_mpg123_context *con = da->priv;
struct mpg123_frameinfo finfo;
if (mpg123_info(con->handle, &finfo) != MPG123_OK)
return;
/* finfo.bitrate is expressed in kilobits */
const int bitrate = finfo.bitrate * 1000;
if (finfo.vbr != MPG123_CBR) {
if (--con->delay < 1) {
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 +
bitrate) / con->mean_count;
da->bitrate = (int) (con->mean_rate + 0.5);
con->delay = 10;
}
} else {
da->bitrate = bitrate ? bitrate : compute_bitrate(&finfo);
con->delay = 1;
con->mean_rate = 0.;
con->mean_count = 0;
}
}
/* libmpg123 has a new format ready; query and store, return return value
of mpg123_getformat() */
static int set_format(struct dec_audio *da)
{
struct ad_mpg123_context *con = da->priv;
int ret;
long rate;
int channels;
int encoding;
ret = mpg123_getformat(con->handle, &rate, &channels, &encoding);
if (ret == MPG123_OK) {
mp_audio_set_num_channels(&da->decoded, channels);
da->decoded.rate = rate;
int af = mpg123_format_to_af(encoding);
if (!af) {
/* This means we got a funny custom build of libmpg123 that only supports an unknown format. */
MP_ERR(da, "Bad encoding from mpg123: %i.\n", encoding);
return MPG123_ERR;
}
mp_audio_set_format(&da->decoded, af);
con->sample_size = channels * af_fmt2bps(af);
}
return ret;
}
static int decode_packet(struct dec_audio *da)
{
struct ad_mpg123_context *con = da->priv;
int ret;
mp_audio_set_null_data(&da->decoded);
struct demux_packet *pkt = demux_read_packet(da->header);
if (!pkt)
return AD_EOF;
/* Next bytes from that presentation time. */
if (pkt->pts != MP_NOPTS_VALUE) {
da->pts = pkt->pts;
da->pts_offset = 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_OK)
goto mpg123_fail;
unsigned char *audio = NULL;
size_t bytes = 0;
ret = mpg123_decode_frame(con->handle, NULL, &audio, &bytes);
if (ret == MPG123_NEED_MORE)
return 0;
if (ret != MPG123_OK && ret != MPG123_DONE && ret != MPG123_NEW_FORMAT)
goto mpg123_fail;
ret = set_format(da);
if (ret != MPG123_OK)
goto mpg123_fail;
if (con->sample_size < 1) {
MP_ERR(da, "no sample size\n");
return AD_ERR;
}
int got_samples = bytes / con->sample_size;
da->decoded.planes[0] = audio;
da->decoded.samples = got_samples;
update_info(da);
return 0;
mpg123_fail:
MP_ERR(da, "mpg123 decoding error: %s\n", mpg123_strerror(con->handle));
return AD_ERR;
}
static int control(struct dec_audio *da, int cmd, void *arg)
{
struct ad_mpg123_context *con = da->priv;
switch (cmd) {
case ADCTRL_RESET:
mp_audio_set_null_data(&da->decoded);
mpg123_close(con->handle);
if (mpg123_open_feed(con->handle) != MPG123_OK) {
MP_ERR(da, "mpg123 failed to reopen stream: %s\n",
mpg123_strerror(con->handle));
return CONTROL_FALSE;
}
return CONTROL_TRUE;
}
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,
.init = init,
.uninit = uninit,
.control = control,
.decode_packet = decode_packet,
};