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mpv/audio/decode/ad_lavc.c
wm4 9c2858f37f ad_lavc: deal with arbitrary decoder delay
Normally, audio decoder don't have a decoder delay, so the code was
fine. But FFmpeg supports multithreaded decoding for some audio codecs,
which introduces such a delay.

The delay means that we won't get decoded audio for the first few
packets, and that we need to do something to get the trailing audio
still buffered in the decoder when reaching EOF.

Two changes are needed to deal with the delay:
- If EOF is reached, pass a "flush" packet to the decoder to return the
  buffered audio. Such a flush packet is automatically setup when
  calling mp_set_av_packet() with a NULL packet.
- Use the PTS returned by the decoder, instead of the packet's. This is
  important to get correct timestamps for decoded audio. Ignoring this
  would result into offsetting the audio playback time by the decoder
  delay. Note that we can still use the timestamp of the first packet
  to get the timestamp for the start of the audio.
2013-12-04 23:12:51 +01:00

417 lines
13 KiB
C

/*
* This file is part of MPlayer.
*
* 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 <stdbool.h>
#include <assert.h>
#include <libavcodec/avcodec.h>
#include <libavutil/opt.h>
#include <libavutil/common.h>
#include "talloc.h"
#include "config.h"
#include "mpvcore/av_common.h"
#include "mpvcore/codecs.h"
#include "mpvcore/mp_msg.h"
#include "mpvcore/options.h"
#include "mpvcore/av_opts.h"
#include "ad.h"
#include "audio/fmt-conversion.h"
#include "compat/libav.h"
struct priv {
AVCodecContext *avctx;
AVFrame *avframe;
struct mp_audio frame;
bool force_channel_map;
struct demux_packet *packet;
};
static void uninit(struct dec_audio *da);
static int decode_new_packet(struct dec_audio *da);
#define OPT_BASE_STRUCT struct MPOpts
const m_option_t ad_lavc_decode_opts_conf[] = {
OPT_FLOATRANGE("ac3drc", ad_lavc_param.ac3drc, 0, 0, 2),
OPT_FLAG("downmix", ad_lavc_param.downmix, 0),
OPT_STRING("o", ad_lavc_param.avopt, 0),
{0}
};
struct pcm_map
{
int tag;
const char *codecs[6]; // {any, 1byte, 2bytes, 3bytes, 4bytes, 8bytes}
};
// NOTE: these are needed to make rawaudio with demux_mkv work.
static const struct pcm_map tag_map[] = {
// Microsoft PCM
{0x0, {NULL, "pcm_u8", "pcm_s16le", "pcm_s24le", "pcm_s32le"}},
{0x1, {NULL, "pcm_u8", "pcm_s16le", "pcm_s24le", "pcm_s32le"}},
// MS PCM, Extended
{0xfffe, {NULL, "pcm_u8", "pcm_s16le", "pcm_s24le", "pcm_s32le"}},
// IEEE float
{0x3, {"pcm_f32le", [5] = "pcm_f64le"}},
// 'raw '
{0x20776172, {"pcm_s16be", [1] = "pcm_u8"}},
// 'twos', used by demux_mkv.c internally
{MKTAG('t', 'w', 'o', 's'),
{NULL, "pcm_s8", "pcm_s16be", "pcm_s24be", "pcm_s32be"}},
{-1},
};
// For demux_rawaudio.c; needed because ffmpeg doesn't have these sample
// formats natively.
static const struct pcm_map af_map[] = {
{AF_FORMAT_U8, {"pcm_u8"}},
{AF_FORMAT_S8, {"pcm_u8"}},
{AF_FORMAT_U16_LE, {"pcm_u16le"}},
{AF_FORMAT_U16_BE, {"pcm_u16be"}},
{AF_FORMAT_S16_LE, {"pcm_s16le"}},
{AF_FORMAT_S16_BE, {"pcm_s16be"}},
{AF_FORMAT_U24_LE, {"pcm_u24le"}},
{AF_FORMAT_U24_BE, {"pcm_u24be"}},
{AF_FORMAT_S24_LE, {"pcm_s24le"}},
{AF_FORMAT_S24_BE, {"pcm_s24be"}},
{AF_FORMAT_U32_LE, {"pcm_u32le"}},
{AF_FORMAT_U32_BE, {"pcm_u32be"}},
{AF_FORMAT_S32_LE, {"pcm_s32le"}},
{AF_FORMAT_S32_BE, {"pcm_s32be"}},
{AF_FORMAT_FLOAT_LE, {"pcm_f32le"}},
{AF_FORMAT_FLOAT_BE, {"pcm_f32be"}},
{AF_FORMAT_DOUBLE_LE, {"pcm_f64le"}},
{AF_FORMAT_DOUBLE_BE, {"pcm_f64be"}},
{-1},
};
static const char *find_pcm_decoder(const struct pcm_map *map, int format,
int bits_per_sample)
{
int bytes = (bits_per_sample + 7) / 8;
if (bytes == 8)
bytes = 5; // 64 bit entry
for (int n = 0; map[n].tag != -1; n++) {
const struct pcm_map *entry = &map[n];
if (entry->tag == format) {
const char *dec = NULL;
if (bytes >= 1 && bytes <= 5)
dec = entry->codecs[bytes];
if (!dec)
dec = entry->codecs[0];
if (dec)
return dec;
}
}
return NULL;
}
static int setup_format(struct dec_audio *da)
{
struct priv *priv = da->priv;
AVCodecContext *lavc_context = priv->avctx;
struct sh_audio *sh_audio = da->header->audio;
// Note: invalid parameters are rejected by dec_audio.c
mp_audio_set_format(&da->decoded, af_from_avformat(lavc_context->sample_fmt));
da->decoded.rate = lavc_context->sample_rate;
if (!da->decoded.rate && sh_audio->wf) {
// If not set, try container samplerate.
// (Maybe this can't happen, and it's an artifact from the past.)
da->decoded.rate = sh_audio->wf->nSamplesPerSec;
mp_tmsg(MSGT_DECAUDIO, MSGL_WARN, "ad_lavc: using container rate.\n");
}
struct mp_chmap lavc_chmap;
mp_chmap_from_lavc(&lavc_chmap, lavc_context->channel_layout);
// No channel layout or layout disagrees with channel count
if (lavc_chmap.num != lavc_context->channels)
mp_chmap_from_channels(&lavc_chmap, lavc_context->channels);
if (priv->force_channel_map) {
if (lavc_chmap.num == sh_audio->channels.num)
lavc_chmap = sh_audio->channels;
}
mp_audio_set_channels(&da->decoded, &lavc_chmap);
return 0;
}
static void set_from_wf(AVCodecContext *avctx, MP_WAVEFORMATEX *wf)
{
avctx->channels = wf->nChannels;
avctx->sample_rate = wf->nSamplesPerSec;
avctx->bit_rate = wf->nAvgBytesPerSec * 8;
avctx->block_align = wf->nBlockAlign;
avctx->bits_per_coded_sample = wf->wBitsPerSample;
if (wf->cbSize > 0) {
avctx->extradata = av_mallocz(wf->cbSize + FF_INPUT_BUFFER_PADDING_SIZE);
avctx->extradata_size = wf->cbSize;
memcpy(avctx->extradata, wf + 1, avctx->extradata_size);
}
}
static int init(struct dec_audio *da, const char *decoder)
{
struct MPOpts *mpopts = da->opts;
struct ad_lavc_param *opts = &mpopts->ad_lavc_param;
AVCodecContext *lavc_context;
AVCodec *lavc_codec;
struct sh_stream *sh = da->header;
struct sh_audio *sh_audio = sh->audio;
struct priv *ctx = talloc_zero(NULL, struct priv);
da->priv = ctx;
if (sh_audio->wf && strcmp(decoder, "pcm") == 0) {
decoder = find_pcm_decoder(tag_map, sh->format,
sh_audio->wf->wBitsPerSample);
} else if (sh_audio->wf && strcmp(decoder, "mp-pcm") == 0) {
decoder = find_pcm_decoder(af_map, sh->format, 0);
ctx->force_channel_map = true;
}
lavc_codec = avcodec_find_decoder_by_name(decoder);
if (!lavc_codec) {
mp_tmsg(MSGT_DECAUDIO, MSGL_ERR,
"Cannot find codec '%s' in libavcodec...\n", decoder);
uninit(da);
return 0;
}
lavc_context = avcodec_alloc_context3(lavc_codec);
ctx->avctx = lavc_context;
ctx->avframe = avcodec_alloc_frame();
lavc_context->codec_type = AVMEDIA_TYPE_AUDIO;
lavc_context->codec_id = lavc_codec->id;
if (opts->downmix) {
lavc_context->request_channels = mpopts->audio_output_channels.num;
lavc_context->request_channel_layout =
mp_chmap_to_lavc(&mpopts->audio_output_channels);
}
// Always try to set - option only exists for AC3 at the moment
av_opt_set_double(lavc_context, "drc_scale", opts->ac3drc,
AV_OPT_SEARCH_CHILDREN);
if (opts->avopt) {
if (parse_avopts(lavc_context, opts->avopt) < 0) {
mp_msg(MSGT_DECVIDEO, MSGL_ERR,
"ad_lavc: setting AVOptions '%s' failed.\n", opts->avopt);
uninit(da);
return 0;
}
}
lavc_context->codec_tag = sh->format;
lavc_context->sample_rate = sh_audio->samplerate;
lavc_context->bit_rate = sh_audio->i_bps * 8;
lavc_context->channel_layout = mp_chmap_to_lavc(&sh_audio->channels);
if (sh_audio->wf)
set_from_wf(lavc_context, sh_audio->wf);
// demux_mkv, demux_mpg
if (sh_audio->codecdata_len && sh_audio->codecdata &&
!lavc_context->extradata) {
lavc_context->extradata = av_malloc(sh_audio->codecdata_len +
FF_INPUT_BUFFER_PADDING_SIZE);
lavc_context->extradata_size = sh_audio->codecdata_len;
memcpy(lavc_context->extradata, (char *)sh_audio->codecdata,
lavc_context->extradata_size);
}
if (sh->lav_headers)
mp_copy_lav_codec_headers(lavc_context, sh->lav_headers);
/* open it */
if (avcodec_open2(lavc_context, lavc_codec, NULL) < 0) {
mp_tmsg(MSGT_DECAUDIO, MSGL_ERR, "Could not open codec.\n");
uninit(da);
return 0;
}
mp_msg(MSGT_DECAUDIO, MSGL_V, "INFO: libavcodec \"%s\" init OK!\n",
lavc_codec->name);
// Decode at least 1 sample: (to get header filled)
for (int tries = 1; ; tries++) {
int x = decode_new_packet(da);
if (x >= 0 && ctx->frame.samples > 0) {
mp_msg(MSGT_DECAUDIO, MSGL_V,
"Initial decode succeeded after %d packets.\n", tries);
break;
}
if (tries >= 50) {
mp_msg(MSGT_DECAUDIO, MSGL_ERR,
"ad_lavc: initial decode failed\n");
uninit(da);
return 0;
}
}
da->i_bps = lavc_context->bit_rate / 8;
if (sh_audio->wf && sh_audio->wf->nAvgBytesPerSec)
da->i_bps = sh_audio->wf->nAvgBytesPerSec;
return 1;
}
static void uninit(struct dec_audio *da)
{
struct priv *ctx = da->priv;
if (!ctx)
return;
AVCodecContext *lavc_context = ctx->avctx;
if (lavc_context) {
if (avcodec_close(lavc_context) < 0)
mp_tmsg(MSGT_DECVIDEO, MSGL_ERR, "Could not close codec.\n");
av_freep(&lavc_context->extradata);
av_freep(&lavc_context);
}
avcodec_free_frame(&ctx->avframe);
}
static int control(struct dec_audio *da, int cmd, void *arg)
{
struct priv *ctx = da->priv;
switch (cmd) {
case ADCTRL_RESET:
avcodec_flush_buffers(ctx->avctx);
ctx->frame.samples = 0;
talloc_free(ctx->packet);
ctx->packet = NULL;
return CONTROL_TRUE;
}
return CONTROL_UNKNOWN;
}
static int decode_new_packet(struct dec_audio *da)
{
struct priv *priv = da->priv;
AVCodecContext *avctx = priv->avctx;
priv->frame.samples = 0;
struct demux_packet *mpkt = priv->packet;
if (!mpkt)
mpkt = demux_read_packet(da->header);
priv->packet = talloc_steal(priv, mpkt);
int in_len = mpkt ? mpkt->len : 0;
AVPacket pkt;
mp_set_av_packet(&pkt, mpkt, NULL);
// If we don't have a PTS yet, use the first packet PTS we can get.
if (da->pts == MP_NOPTS_VALUE && mpkt && mpkt->pts != MP_NOPTS_VALUE) {
da->pts = mpkt->pts;
da->pts_offset = 0;
}
int got_frame = 0;
int ret = avcodec_decode_audio4(avctx, priv->avframe, &got_frame, &pkt);
if (mpkt) {
// At least "shorten" decodes sub-frames, instead of the whole packet.
// At least "mpc8" can return 0 and wants the packet again next time.
if (ret >= 0) {
ret = FFMIN(ret, mpkt->len); // sanity check against decoder overreads
mpkt->buffer += ret;
mpkt->len -= ret;
mpkt->pts = MP_NOPTS_VALUE; // don't reset PTS next time
}
if (mpkt->len == 0 || ret < 0) {
talloc_free(mpkt);
priv->packet = NULL;
}
}
// LATM may need many packets to find mux info
if (ret == AVERROR(EAGAIN))
return 0;
if (ret < 0) {
mp_msg(MSGT_DECAUDIO, MSGL_V, "lavc_audio: error\n");
return -1;
}
if (!got_frame)
return mpkt ? 0 : -1; // -1: eof
if (setup_format(da) < 0)
return -1;
priv->frame.samples = priv->avframe->nb_samples;
mp_audio_copy_config(&priv->frame, &da->decoded);
for (int n = 0; n < priv->frame.num_planes; n++)
priv->frame.planes[n] = priv->avframe->data[n];
double out_pts = mp_pts_from_av(priv->avframe->pkt_pts, NULL);
if (out_pts != MP_NOPTS_VALUE) {
da->pts = out_pts;
da->pts_offset = 0;
}
mp_dbg(MSGT_DECAUDIO, MSGL_DBG2, "Decoded %d -> %d samples\n", in_len,
priv->frame.samples);
return 0;
}
static int decode_audio(struct dec_audio *da, struct mp_audio *buffer, int maxlen)
{
struct priv *priv = da->priv;
if (!priv->frame.samples) {
if (decode_new_packet(da) < 0)
return -1;
}
if (!mp_audio_config_equals(buffer, &priv->frame))
return 0;
buffer->samples = MPMIN(priv->frame.samples, maxlen);
mp_audio_copy(buffer, 0, &priv->frame, 0, buffer->samples);
mp_audio_skip_samples(&priv->frame, buffer->samples);
da->pts_offset += buffer->samples;
return 0;
}
static void add_decoders(struct mp_decoder_list *list)
{
mp_add_lavc_decoders(list, AVMEDIA_TYPE_AUDIO);
mp_add_decoder(list, "lavc", "pcm", "pcm", "Raw PCM");
mp_add_decoder(list, "lavc", "mp-pcm", "mp-pcm", "Raw PCM");
}
const struct ad_functions ad_lavc = {
.name = "lavc",
.add_decoders = add_decoders,
.init = init,
.uninit = uninit,
.control = control,
.decode_audio = decode_audio,
};