yading@10: /*
yading@10:  * Copyright (c) 2011 Nicolas George <nicolas.george@normalesup.org>
yading@10:  *
yading@10:  * This file is part of FFmpeg.
yading@10:  *
yading@10:  * FFmpeg is free software; you can redistribute it and/or
yading@10:  * modify it under the terms of the GNU Lesser General Public
yading@10:  * License as published by the Free Software Foundation; either
yading@10:  * version 2.1 of the License, or (at your option) any later version.
yading@10:  *
yading@10:  * FFmpeg is distributed in the hope that it will be useful,
yading@10:  * but WITHOUT ANY WARRANTY; without even the implied warranty of
yading@10:  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
yading@10:  * GNU Lesser General Public License for more details.
yading@10:  *
yading@10:  * You should have received a copy of the GNU Lesser General Public
yading@10:  * License along with FFmpeg; if not, write to the Free Software
yading@10:  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
yading@10:  */
yading@10: 
yading@10: /**
yading@10:  * @file
yading@10:  * Stream (de)synchronization filter
yading@10:  */
yading@10: 
yading@10: #include "libavutil/eval.h"
yading@10: #include "libavutil/opt.h"
yading@10: #include "avfilter.h"
yading@10: #include "audio.h"
yading@10: #include "internal.h"
yading@10: 
yading@10: #define QUEUE_SIZE 16
yading@10: 
yading@10: static const char * const var_names[] = {
yading@10:     "b1", "b2",
yading@10:     "s1", "s2",
yading@10:     "t1", "t2",
yading@10:     NULL
yading@10: };
yading@10: 
yading@10: enum var_name {
yading@10:     VAR_B1, VAR_B2,
yading@10:     VAR_S1, VAR_S2,
yading@10:     VAR_T1, VAR_T2,
yading@10:     VAR_NB
yading@10: };
yading@10: 
yading@10: typedef struct {
yading@10:     const AVClass *class;
yading@10:     AVExpr *expr;
yading@10:     char *expr_str;
yading@10:     double var_values[VAR_NB];
yading@10:     struct buf_queue {
yading@10:         AVFrame *buf[QUEUE_SIZE];
yading@10:         unsigned tail, nb;
yading@10:         /* buf[tail] is the oldest,
yading@10:            buf[(tail + nb) % QUEUE_SIZE] is where the next is added */
yading@10:     } queue[2];
yading@10:     int req[2];
yading@10:     int next_out;
yading@10:     int eof; /* bitmask, one bit for each stream */
yading@10: } AStreamSyncContext;
yading@10: 
yading@10: #define OFFSET(x) offsetof(AStreamSyncContext, x)
yading@10: #define FLAGS AV_OPT_FLAG_AUDIO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
yading@10: static const AVOption astreamsync_options[] = {
yading@10:     { "expr", "set stream selection expression", OFFSET(expr_str), AV_OPT_TYPE_STRING, { .str = "t1-t2" }, .flags = FLAGS },
yading@10:     { "e",    "set stream selection expression", OFFSET(expr_str), AV_OPT_TYPE_STRING, { .str = "t1-t2" }, .flags = FLAGS },
yading@10:     { NULL }
yading@10: };
yading@10: 
yading@10: AVFILTER_DEFINE_CLASS(astreamsync);
yading@10: 
yading@10: static av_cold int init(AVFilterContext *ctx)
yading@10: {
yading@10:     AStreamSyncContext *as = ctx->priv;
yading@10:     int r, i;
yading@10: 
yading@10:     r = av_expr_parse(&as->expr, as->expr_str, var_names,
yading@10:                       NULL, NULL, NULL, NULL, 0, ctx);
yading@10:     if (r < 0) {
yading@10:         av_log(ctx, AV_LOG_ERROR, "Error in expression \"%s\"\n", as->expr_str);
yading@10:         return r;
yading@10:     }
yading@10:     for (i = 0; i < 42; i++)
yading@10:         av_expr_eval(as->expr, as->var_values, NULL); /* exercize prng */
yading@10:     return 0;
yading@10: }
yading@10: 
yading@10: static int query_formats(AVFilterContext *ctx)
yading@10: {
yading@10:     int i;
yading@10:     AVFilterFormats *formats, *rates;
yading@10:     AVFilterChannelLayouts *layouts;
yading@10: 
yading@10:     for (i = 0; i < 2; i++) {
yading@10:         formats = ctx->inputs[i]->in_formats;
yading@10:         ff_formats_ref(formats, &ctx->inputs[i]->out_formats);
yading@10:         ff_formats_ref(formats, &ctx->outputs[i]->in_formats);
yading@10:         rates = ff_all_samplerates();
yading@10:         ff_formats_ref(rates, &ctx->inputs[i]->out_samplerates);
yading@10:         ff_formats_ref(rates, &ctx->outputs[i]->in_samplerates);
yading@10:         layouts = ctx->inputs[i]->in_channel_layouts;
yading@10:         ff_channel_layouts_ref(layouts, &ctx->inputs[i]->out_channel_layouts);
yading@10:         ff_channel_layouts_ref(layouts, &ctx->outputs[i]->in_channel_layouts);
yading@10:     }
yading@10:     return 0;
yading@10: }
yading@10: 
yading@10: static int config_output(AVFilterLink *outlink)
yading@10: {
yading@10:     AVFilterContext *ctx = outlink->src;
yading@10:     int id = outlink == ctx->outputs[1];
yading@10: 
yading@10:     outlink->sample_rate = ctx->inputs[id]->sample_rate;
yading@10:     outlink->time_base   = ctx->inputs[id]->time_base;
yading@10:     return 0;
yading@10: }
yading@10: 
yading@10: static int send_out(AVFilterContext *ctx, int out_id)
yading@10: {
yading@10:     AStreamSyncContext *as = ctx->priv;
yading@10:     struct buf_queue *queue = &as->queue[out_id];
yading@10:     AVFrame *buf = queue->buf[queue->tail];
yading@10:     int ret;
yading@10: 
yading@10:     queue->buf[queue->tail] = NULL;
yading@10:     as->var_values[VAR_B1 + out_id]++;
yading@10:     as->var_values[VAR_S1 + out_id] += buf->nb_samples;
yading@10:     if (buf->pts != AV_NOPTS_VALUE)
yading@10:         as->var_values[VAR_T1 + out_id] =
yading@10:             av_q2d(ctx->outputs[out_id]->time_base) * buf->pts;
yading@10:     as->var_values[VAR_T1 + out_id] += buf->nb_samples /
yading@10:                                    (double)ctx->inputs[out_id]->sample_rate;
yading@10:     ret = ff_filter_frame(ctx->outputs[out_id], buf);
yading@10:     queue->nb--;
yading@10:     queue->tail = (queue->tail + 1) % QUEUE_SIZE;
yading@10:     if (as->req[out_id])
yading@10:         as->req[out_id]--;
yading@10:     return ret;
yading@10: }
yading@10: 
yading@10: static void send_next(AVFilterContext *ctx)
yading@10: {
yading@10:     AStreamSyncContext *as = ctx->priv;
yading@10:     int i;
yading@10: 
yading@10:     while (1) {
yading@10:         if (!as->queue[as->next_out].nb)
yading@10:             break;
yading@10:         send_out(ctx, as->next_out);
yading@10:         if (!as->eof)
yading@10:             as->next_out = av_expr_eval(as->expr, as->var_values, NULL) >= 0;
yading@10:     }
yading@10:     for (i = 0; i < 2; i++)
yading@10:         if (as->queue[i].nb == QUEUE_SIZE)
yading@10:             send_out(ctx, i);
yading@10: }
yading@10: 
yading@10: static int request_frame(AVFilterLink *outlink)
yading@10: {
yading@10:     AVFilterContext *ctx = outlink->src;
yading@10:     AStreamSyncContext *as = ctx->priv;
yading@10:     int id = outlink == ctx->outputs[1];
yading@10: 
yading@10:     as->req[id]++;
yading@10:     while (as->req[id] && !(as->eof & (1 << id))) {
yading@10:         if (as->queue[as->next_out].nb) {
yading@10:             send_next(ctx);
yading@10:         } else {
yading@10:             as->eof |= 1 << as->next_out;
yading@10:             ff_request_frame(ctx->inputs[as->next_out]);
yading@10:             if (as->eof & (1 << as->next_out))
yading@10:                 as->next_out = !as->next_out;
yading@10:         }
yading@10:     }
yading@10:     return 0;
yading@10: }
yading@10: 
yading@10: static int filter_frame(AVFilterLink *inlink, AVFrame *insamples)
yading@10: {
yading@10:     AVFilterContext *ctx = inlink->dst;
yading@10:     AStreamSyncContext *as = ctx->priv;
yading@10:     int id = inlink == ctx->inputs[1];
yading@10: 
yading@10:     as->queue[id].buf[(as->queue[id].tail + as->queue[id].nb++) % QUEUE_SIZE] =
yading@10:         insamples;
yading@10:     as->eof &= ~(1 << id);
yading@10:     send_next(ctx);
yading@10:     return 0;
yading@10: }
yading@10: 
yading@10: static av_cold void uninit(AVFilterContext *ctx)
yading@10: {
yading@10:     AStreamSyncContext *as = ctx->priv;
yading@10: 
yading@10:     av_expr_free(as->expr);
yading@10:     as->expr = NULL;
yading@10: }
yading@10: 
yading@10: static const AVFilterPad astreamsync_inputs[] = {
yading@10:     {
yading@10:         .name         = "in1",
yading@10:         .type         = AVMEDIA_TYPE_AUDIO,
yading@10:         .filter_frame = filter_frame,
yading@10:     },{
yading@10:         .name         = "in2",
yading@10:         .type         = AVMEDIA_TYPE_AUDIO,
yading@10:         .filter_frame = filter_frame,
yading@10:     },
yading@10:     { NULL }
yading@10: };
yading@10: 
yading@10: static const AVFilterPad astreamsync_outputs[] = {
yading@10:     {
yading@10:         .name          = "out1",
yading@10:         .type          = AVMEDIA_TYPE_AUDIO,
yading@10:         .config_props  = config_output,
yading@10:         .request_frame = request_frame,
yading@10:     },{
yading@10:         .name          = "out2",
yading@10:         .type          = AVMEDIA_TYPE_AUDIO,
yading@10:         .config_props  = config_output,
yading@10:         .request_frame = request_frame,
yading@10:     },
yading@10:     { NULL }
yading@10: };
yading@10: 
yading@10: AVFilter avfilter_af_astreamsync = {
yading@10:     .name          = "astreamsync",
yading@10:     .description   = NULL_IF_CONFIG_SMALL("Copy two streams of audio data "
yading@10:                                           "in a configurable order."),
yading@10:     .priv_size     = sizeof(AStreamSyncContext),
yading@10:     .init          = init,
yading@10:     .uninit        = uninit,
yading@10:     .query_formats = query_formats,
yading@10:     .inputs        = astreamsync_inputs,
yading@10:     .outputs       = astreamsync_outputs,
yading@10:     .priv_class    = &astreamsync_class,
yading@10: };