mpv/audio/filter/af_lavcac3enc.c

454 lines
13 KiB
C

/*
* audio filter for runtime AC-3 encoding with libavcodec.
*
* Copyright (C) 2007 Ulion <ulion A gmail P com>
*
* This file is part of mpv.
*
* mpv 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.
*
* mpv 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 mpv. If not, see <http://www.gnu.org/licenses/>.
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <inttypes.h>
#include <assert.h>
#include <libavcodec/avcodec.h>
#include <libavutil/intreadwrite.h>
#include <libavutil/common.h>
#include <libavutil/bswap.h>
#include <libavutil/mem.h>
#include "config.h"
#include "common/av_common.h"
#include "common/common.h"
#include "af.h"
#include "audio/audio_buffer.h"
#include "audio/chmap_sel.h"
#include "audio/fmt-conversion.h"
#define AC3_MAX_CHANNELS 6
#define AC3_MAX_CODED_FRAME_SIZE 3840
#define AC3_FRAME_SIZE (6 * 256)
const uint16_t ac3_bitrate_tab[19] = {
32, 40, 48, 56, 64, 80, 96, 112, 128,
160, 192, 224, 256, 320, 384, 448, 512, 576, 640
};
// Data for specific instances of this filter
typedef struct af_ac3enc_s {
struct AVCodec *lavc_acodec;
struct AVCodecContext *lavc_actx;
int bit_rate;
struct mp_audio *input; // frame passed to libavcodec
struct mp_audio *pending; // unconsumed input data
int in_samples; // samples of input per AC3 frame
int out_samples; // upper bound on encoded output per AC3 frame
int64_t encoder_buffered;
int cfg_add_iec61937_header;
int cfg_bit_rate;
int cfg_min_channel_num;
char *cfg_encoder;
char **cfg_avopts;
} af_ac3enc_t;
// fmt carries the input format. Change it to the best next-possible format
// the encoder likely accepts.
static void select_encode_format(AVCodecContext *c, struct mp_audio *fmt)
{
int formats[AF_FORMAT_COUNT];
af_get_best_sample_formats(fmt->format, formats);
for (int n = 0; formats[n]; n++) {
const enum AVSampleFormat *lf = c->codec->sample_fmts;
for (int i = 0; lf && lf[i] != AV_SAMPLE_FMT_NONE; i++) {
int mpfmt = af_from_avformat(lf[i]);
if (mpfmt && mpfmt == formats[n]) {
mp_audio_set_format(fmt, mpfmt);
goto done_fmt;
}
}
}
done_fmt: ;
int rate =
af_select_best_samplerate(fmt->rate, c->codec->supported_samplerates);
if (rate > 0)
fmt->rate = rate;
struct mp_chmap_sel sel = {0};
const uint64_t *lch = c->codec->channel_layouts;
for (int n = 0; lch && lch[n]; n++) {
struct mp_chmap chmap = {0};
mp_chmap_from_lavc(&chmap, lch[n]);
mp_chmap_sel_add_map(&sel, &chmap);
}
struct mp_chmap res = fmt->channels;
mp_chmap_sel_adjust(&sel, &res);
if (!mp_chmap_is_empty(&res))
mp_audio_set_channels(fmt, &res);
}
// Initialization and runtime control
static int control(struct af_instance *af, int cmd, void *arg)
{
af_ac3enc_t *s = af->priv;
static const int default_bit_rate[AC3_MAX_CHANNELS+1] = \
{0, 96000, 192000, 256000, 384000, 448000, 448000};
switch (cmd){
case AF_CONTROL_REINIT: {
struct mp_audio *in = arg;
struct mp_audio orig_in = *in;
if (!af_fmt_is_pcm(in->format) || in->nch < s->cfg_min_channel_num)
return AF_DETACH;
// At least currently, the AC3 encoder doesn't export sample rates.
in->rate = 48000;
select_encode_format(s->lavc_actx, in);
af->data->rate = in->rate;
mp_audio_set_format(af->data, AF_FORMAT_S_AC3);
mp_audio_set_num_channels(af->data, 2);
if (!mp_audio_config_equals(in, &orig_in))
return AF_FALSE;
if (s->cfg_add_iec61937_header) {
s->out_samples = AC3_FRAME_SIZE;
} else {
s->out_samples = AC3_MAX_CODED_FRAME_SIZE / af->data->sstride;
}
mp_audio_copy_config(s->input, in);
talloc_free(s->pending);
s->pending = NULL;
MP_DBG(af, "reinit: %d, %d, %d.\n", in->nch, in->rate, s->in_samples);
int bit_rate = s->bit_rate ? s->bit_rate : default_bit_rate[in->nch];
if (s->lavc_actx->channels != in->nch ||
s->lavc_actx->sample_rate != in->rate ||
s->lavc_actx->bit_rate != bit_rate)
{
avcodec_close(s->lavc_actx);
// Put sample parameters
s->lavc_actx->sample_fmt = af_to_avformat(in->format);
s->lavc_actx->channels = in->nch;
s->lavc_actx->channel_layout = mp_chmap_to_lavc(&in->channels);
s->lavc_actx->sample_rate = in->rate;
s->lavc_actx->bit_rate = bit_rate;
if (avcodec_open2(s->lavc_actx, s->lavc_acodec, NULL) < 0) {
MP_ERR(af, "Couldn't open codec %s, br=%d.\n", "ac3", bit_rate);
return AF_ERROR;
}
if (s->lavc_actx->frame_size < 1) {
MP_ERR(af, "encoder didn't specify input frame size\n");
return AF_ERROR;
}
}
s->in_samples = s->lavc_actx->frame_size;
mp_audio_realloc(s->input, s->in_samples);
s->input->samples = 0;
s->encoder_buffered = 0;
return AF_OK;
}
case AF_CONTROL_RESET:
if (avcodec_is_open(s->lavc_actx))
avcodec_flush_buffers(s->lavc_actx);
talloc_free(s->pending);
s->pending = NULL;
s->input->samples = 0;
s->encoder_buffered = 0;
return AF_OK;
}
return AF_UNKNOWN;
}
// Deallocate memory
static void uninit(struct af_instance* af)
{
af_ac3enc_t *s = af->priv;
if (s) {
if(s->lavc_actx) {
avcodec_close(s->lavc_actx);
av_free(s->lavc_actx);
}
talloc_free(s->pending);
}
}
static void update_delay(struct af_instance *af)
{
af_ac3enc_t *s = af->priv;
af->delay = ((s->pending ? s->pending->samples : 0) + s->input->samples +
s->encoder_buffered) / (double)s->input->rate;
}
static int filter_frame(struct af_instance *af, struct mp_audio *audio)
{
af_ac3enc_t *s = af->priv;
// filter_output must have been called until no output was produced.
if (s->pending && s->pending->samples)
MP_ERR(af, "broken data flow\n");
talloc_free(s->pending);
s->pending = audio;
update_delay(af);
return 0;
}
static void swap_16(uint16_t *ptr, size_t size)
{
for (size_t n = 0; n < size; n++)
ptr[n] = av_bswap16(ptr[n]);
}
// Copy data from input frame to encode frame (because libavcodec wants a full
// AC3 frame for encoding, while filter input frames can be smaller or larger).
// Return true if the frame is complete.
static bool fill_buffer(struct af_instance *af)
{
af_ac3enc_t *s = af->priv;
af->delay = 0;
if (s->pending) {
if (!mp_audio_is_writeable(s->input))
assert(s->input->samples == 0); // we can't have sent a partial frame
mp_audio_realloc_min(s->input, s->in_samples);
int copy = MPMIN(s->in_samples - s->input->samples, s->pending->samples);
s->input->samples += copy;
mp_audio_copy(s->input, s->input->samples - copy, s->pending, 0, copy);
mp_audio_skip_samples(s->pending, copy);
}
update_delay(af);
return s->input->samples >= s->in_samples;
}
// Return <0 on error, 0 on need more input, 1 on success (and *frame set).
// To actually advance the read pointer, set s->input->samples=0 afterwards.
static int read_input_frame(struct af_instance *af, AVFrame *frame)
{
af_ac3enc_t *s = af->priv;
if (!fill_buffer(af))
return 0; // need more input
if (mp_audio_to_avframe(s->input, frame) < 0)
return -1;
return 1;
}
static int filter_out(struct af_instance *af)
{
af_ac3enc_t *s = af->priv;
if (!s->pending)
return 0;
AVFrame *frame = av_frame_alloc();
if (!frame) {
MP_FATAL(af, "Could not allocate memory \n");
return -1;
}
int err = -1;
AVPacket pkt = {0};
av_init_packet(&pkt);
#if HAVE_AVCODEC_NEW_CODEC_API
// Send input as long as it wants.
while (1) {
err = read_input_frame(af, frame);
if (err < 0)
goto done;
if (err == 0)
break;
err = -1;
int lavc_ret = avcodec_send_frame(s->lavc_actx, frame);
// On EAGAIN, we're supposed to read remaining output.
if (lavc_ret == AVERROR(EAGAIN))
break;
if (lavc_ret < 0) {
MP_FATAL(af, "Encode failed.\n");
goto done;
}
s->encoder_buffered += s->input->samples;
s->input->samples = 0;
}
int lavc_ret = avcodec_receive_packet(s->lavc_actx, &pkt);
if (lavc_ret == AVERROR(EAGAIN)) {
// Need to buffer more input.
err = 0;
goto done;
}
if (lavc_ret < 0) {
MP_FATAL(af, "Encode failed.\n");
goto done;
}
#else
err = read_input_frame(af, frame);
if (err < 0)
goto done;
if (err == 0)
goto done;
err = -1;
int ok;
int lavc_ret = avcodec_encode_audio2(s->lavc_actx, &pkt, frame, &ok);
s->input->samples = 0;
if (lavc_ret < 0 || !ok) {
MP_FATAL(af, "Encode failed.\n");
goto done;
}
#endif
MP_DBG(af, "avcodec_encode_audio got %d, pending %d.\n",
pkt.size, s->pending->samples + s->input->samples);
s->encoder_buffered -= AC3_FRAME_SIZE;
struct mp_audio *out =
mp_audio_pool_get(af->out_pool, af->data, s->out_samples);
if (!out)
goto done;
mp_audio_copy_attributes(out, s->pending);
int frame_size = pkt.size;
int header_len = 0;
char hdr[8];
if (s->cfg_add_iec61937_header && pkt.size > 5) {
int bsmod = pkt.data[5] & 0x7;
int len = frame_size;
frame_size = AC3_FRAME_SIZE * 2 * 2;
header_len = 8;
AV_WL16(hdr, 0xF872); // iec 61937 syncword 1
AV_WL16(hdr + 2, 0x4E1F); // iec 61937 syncword 2
hdr[5] = bsmod; // bsmod
hdr[4] = 0x01; // data-type ac3
AV_WL16(hdr + 6, len << 3); // number of bits in payload
}
if (frame_size > out->samples * out->sstride)
abort();
char *buf = (char *)out->planes[0];
memcpy(buf, hdr, header_len);
memcpy(buf + header_len, pkt.data, pkt.size);
memset(buf + header_len + pkt.size, 0,
frame_size - (header_len + pkt.size));
swap_16((uint16_t *)(buf + header_len), pkt.size / 2);
out->samples = frame_size / out->sstride;
af_add_output_frame(af, out);
err = 0;
done:
av_packet_unref(&pkt);
av_frame_free(&frame);
update_delay(af);
return err;
}
static int af_open(struct af_instance* af){
af_ac3enc_t *s = af->priv;
af->control=control;
af->uninit=uninit;
af->filter_frame = filter_frame;
af->filter_out = filter_out;
s->lavc_acodec = avcodec_find_encoder_by_name(s->cfg_encoder);
if (!s->lavc_acodec) {
MP_ERR(af, "Couldn't find encoder %s.\n", s->cfg_encoder);
return AF_ERROR;
}
s->lavc_actx = avcodec_alloc_context3(s->lavc_acodec);
if (!s->lavc_actx) {
MP_ERR(af, "Audio LAVC, couldn't allocate context!\n");
return AF_ERROR;
}
if (mp_set_avopts(af->log, s->lavc_actx, s->cfg_avopts) < 0)
return AF_ERROR;
// For this one, we require the decoder to expert lists of all supported
// parameters. (Not all decoders do that, but the ones we're interested
// in do.)
if (!s->lavc_acodec->sample_fmts ||
!s->lavc_acodec->channel_layouts)
{
MP_ERR(af, "Audio encoder doesn't list supported parameters.\n");
return AF_ERROR;
}
s->input = talloc_zero(s, struct mp_audio);
if (s->cfg_bit_rate) {
int i;
for (i = 0; i < 19; i++) {
if (ac3_bitrate_tab[i] == s->cfg_bit_rate) {
s->bit_rate = ac3_bitrate_tab[i] * 1000;
break;
}
}
if (i >= 19) {
MP_WARN(af, "unable set unsupported bitrate %d, use default "
"bitrate (check manpage to see supported bitrates).\n",
s->cfg_bit_rate);
}
}
return AF_OK;
}
#define OPT_BASE_STRUCT struct af_ac3enc_s
const struct af_info af_info_lavcac3enc = {
.info = "runtime encode to ac3 using libavcodec",
.name = "lavcac3enc",
.open = af_open,
.priv_size = sizeof(struct af_ac3enc_s),
.priv_defaults = &(const struct af_ac3enc_s){
.cfg_add_iec61937_header = 1,
.cfg_bit_rate = 640,
.cfg_min_channel_num = 3,
.cfg_encoder = "ac3",
},
.options = (const struct m_option[]) {
OPT_FLAG("tospdif", cfg_add_iec61937_header, 0),
OPT_CHOICE_OR_INT("bitrate", cfg_bit_rate, 0, 32, 640,
({"auto", 0}, {"default", 0})),
OPT_INTRANGE("minch", cfg_min_channel_num, 0, 2, 6),
OPT_STRING("encoder", cfg_encoder, 0),
OPT_KEYVALUELIST("o", cfg_avopts, 0),
{0}
},
};