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mpv/libmpcodecs/ad_mpg123.c
diego f1773d911a ad_mpeg123: Enable robust resync
This prevents the decoder from giving up give after long pieces of invalid
data, for example during transmission errors with DVB-T and similar.

patch by Thomas Orgis, thomas-forum orgis org

git-svn-id: svn://svn.mplayerhq.hu/mplayer/trunk@31732 b3059339-0415-0410-9bf9-f77b7e298cf2
2010-11-02 04:14:44 +02:00

580 lines
20 KiB
C

/*
* MPEG 1.0/2.0/2.5 audio layer I, II, III decoding with libmpg123
*
* Copyright (C) 2010 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"
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)
#include "libvo/fastmemcpy.h"
/* We avoid any usage of mpg123 API that is sensitive to the large file
* support setting. This ensures compatibility with a wide range of libmpg123
* installs. This code is intended to work with version 1.0.0 of libmpg123.
*
* Though the chosen API subset is not affected by the choice of large file
* support, the mpg123 header (old versions of which) might include a check
* for matching _FILE_OFFSET_BITS. Since MPlayer does always define this one
* for large file support, we are safe for any default mpg123 install that
* either doesn't have such checks or defaults to the large value of
* _FILE_OFFSET_BITS .
* So, in short: There's no worry unless you have a non-default libmpg123
* with intentionally disabled large file support. */
/* You might need to #undef _FILE_OFFSET_BITS here on a 64 bit system
with released mpg123 1.12 when using callback API. SVN snapshots
should work fine. */
#include <mpg123.h>
/* Selection of mpg123 usage patterns:
* AD_MPG123_CALLBACK: Use callback API instead of feeding of memory buffers.
* That needs mpg123>=1.12, on x86-64 SVN snapshot because of
* _FILE_OFFSET_BITS being defined (see above).
* AD_MPG123_PACKET: Use packet-based input (including pts handling).
* AD_MPG123_SEEKBUFFER: Use internal mpg123 buffer to enhance stream parsing.
* Makes sense with callback API only.
* Any of those might affect I/O performance, might be significant compared
* to the excessively optimized decoding.
*/
/* #define AD_MPG123_CALLBACK */
#define AD_MPG123_PACKET
/* #define AD_MPG123_SEEKBUFFER */
/* 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;
#if (defined AD_MPG123_CALLBACK) && (defined AD_MPG123_PACKET)
unsigned char *packet;
int packleft;
#endif
};
static void context_reset(struct ad_mpg123_context *con)
{
#ifdef AD_MPG123_MEAN_BITRATE
con->mean_rate = 0.;
con->mean_count = 0;
con->delay = 1;
#endif
#if (defined AD_MPG123_CALLBACK) && (defined AD_MPG123_PACKET)
con->packet = NULL;
con->packleft = 0;
#endif
}
#ifdef AD_MPG123_CALLBACK
/* Mpg123 calls that for retrieving data.
* This wrapper is at least needed for the call frame (ssize_t vs. int). */
static ssize_t read_callback(void *ash, void *buf, size_t count)
{
sh_audio_t *sh = ash;
#ifdef AD_MPG123_PACKET
struct ad_mpg123_context *con = sh->context;
unsigned char *target = buf;
int need = count;
ssize_t got = 0;
while (need > 0) {
if (con->packleft > 0) {
int get = need > con->packleft ? con->packleft : need;
/* Any difference to normal memcpy? */
fast_memcpy(target, con->packet, get);
/* OK, that does look redundant. */
con->packet += get;
con->packleft -= get;
target += get;
need -= get;
got += get;
} else {
double pts;
/* Feed more input data. */
con->packleft = ds_get_packet_pts(sh->ds, &con->packet, &pts);
if (con->packleft <= 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;
}
}
}
return got;
#else
/* It returns int... with the meaning of byte count. */
return (ssize_t) demux_read_data(sh->ds, buf, count);
#endif
}
/* Arbitrary input seeking is not supported with this MPlayer API(?).
That also means that we won't read any ID3v1 tags. */
static off_t seek_callback(void *sh, off_t pos, int whence)
{
return -1;
}
#endif
/* 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;
context_reset(con);
/* Auto-choice of optimized decoder (first argument NULL). */
con->handle = mpg123_new(NULL, &err);
if (!con->handle)
goto bad_end;
#ifdef CONFIG_FAKE_MONO
/* 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;
#endif
#ifdef AD_MPG123_CALLBACK
/* The I/O is handled via callbacks to MPlayer stream functions,
* actually only the reading, as general seeking does not seem to be available */
if (mpg123_replace_reader_handle(con->handle, read_callback,
seek_callback, NULL) != MPG123_OK) {
mp_msg(MSGT_DECAUDIO, MSGL_ERR, "mpg123 error: %s\n",
mpg123_strerror(con->handle));
mpg123_exit();
return 0;
}
#endif
/* 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);
/* Old headers don't know MPG123_SEEKBUFFER yet, so use the plain 0x100. */
#ifdef AD_MPG123_SEEKBUFFER
mpg123_param(con->handle, MPG123_ADD_FLAGS, 0x100, 0.0);
#endif
/* 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. */
/* Example for RVA choice (available since libmpg123 1.0.0):
mpg123_param(con->handle, MPG123_RVA, MPG123_RVA_MIX, 0.0) */
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]);
}
#ifndef AD_MPG123_CALLBACK
/* 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 implicitly handled in reopen_stream(). */
do {
size_t got_now = 0;
ret = mpg123_decode(con->handle, NULL, 0, buf + got, count - got,
&got_now);
got += got_now;
#ifdef AD_MPG123_PACKET
sh->pts_bytes += got_now;
#endif
if (ret == MPG123_NEED_MORE) {
int incount;
#ifdef AD_MPG123_PACKET
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;
}
#else
const int inbufsize = 4096;
unsigned char inbuf[inbufsize];
/* Feed more input data. */
incount = demux_read_data(((sh_audio_t *) sh)->ds,
inbuf, inbufsize);
if (incount == 0)
break; /* Apparently that's it. EOF. */
#endif
/* Do not use mpg123_feed(), added in later libmpg123 versions. */
ret = mpg123_decode(con->handle, inbuf, incount, NULL, 0, NULL);
/* Return value is checked in the loop condition.
* It could be MPG12_OK now, it could need more. */
}
/* Older mpg123 versions might indicate MPG123_DONE, so be prepared. */
else if (ret == MPG123_ERR || ret == MPG123_DONE)
break;
} while (ret == MPG123_NEED_MORE || got < count);
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;
}
#endif
/* 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)
{
long rate;
int chan, enc;
struct ad_mpg123_context *con = (struct ad_mpg123_context*) sh->context;
mpg123_close(con->handle);
context_reset(con);
#ifdef AD_MPG123_CALLBACK
if (MPG123_OK == mpg123_open_handle(con->handle, sh) &&
#else
if (/* Open and make sure we have fed enough data to get stream properties. */
MPG123_OK == mpg123_open_feed(con->handle) &&
/* Feed data until mpg123 is ready (has found stream beginning). */
!decode_a_bit(sh, NULL, 0) &&
#endif
/* Not handing NULL pointers for compatibility with old libmpg123. */
MPG123_OK == mpg123_getformat(con->handle, &rate, &chan, &enc)) {
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;
context_reset(con);
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;
}
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;
#ifdef AD_MPG123_CALLBACK
struct ad_mpg123_context *con = sh->context;
size_t got_bytes = 0;
if (MPG123_ERR == mpg123_read(con->handle, buf, minlen, &got_bytes)) {
mp_msg(MSGT_DECAUDIO, MSGL_ERR, "Decoding error in mpg123: %s\n",
mpg123_strerror(con->handle));
return -1;
}
#ifdef AD_MPG123_PACKET
sh->pts_bytes += got_bytes;
#endif
bytes = got_bytes;
#else
bytes = decode_a_bit(sh, buf, minlen);
#endif
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 {
mp_msg(MSGT_DECAUDIO, MSGL_ERR,
"mpg123 cannot reopen stream for resync.\n");
return CONTROL_FALSE;
}
break;
}
return CONTROL_UNKNOWN;
}