2 * Copyright (c) 2011 Nicolas George <nicolas.george@normalesup.org>
4 * This file is part of FFmpeg.
6 * FFmpeg is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Lesser General Public
8 * License as published by the Free Software Foundation; either
9 * version 2.1 of the License, or (at your option) any later version.
11 * FFmpeg is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
16 * You should have received a copy of the GNU Lesser General Public
17 * License along with FFmpeg; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
23 * Stream (de)synchronization filter
26 #include "libavutil/eval.h"
33 static const char * const var_names[] = {
49 double var_values[VAR_NB];
51 AVFilterBufferRef *buf[QUEUE_SIZE];
53 /* buf[tail] is the oldest,
54 buf[(tail + nb) % QUEUE_SIZE] is where the next is added */
58 int eof; /* bitmask, one bit for each stream */
61 static const char *default_expr = "t1-t2";
63 static av_cold int init(AVFilterContext *ctx, const char *args0, void *opaque)
65 AStreamSyncContext *as = ctx->priv;
66 const char *expr = args0 ? args0 : default_expr;
69 r = av_expr_parse(&as->expr, expr, var_names,
70 NULL, NULL, NULL, NULL, 0, ctx);
72 av_log(ctx, AV_LOG_ERROR, "Error in expression \"%s\"\n", expr);
75 for (i = 0; i < 42; i++)
76 av_expr_eval(as->expr, as->var_values, NULL); /* exercize prng */
80 static int query_formats(AVFilterContext *ctx)
83 AVFilterFormats *formats;
84 AVFilterChannelLayouts *layouts;
86 for (i = 0; i < 2; i++) {
87 formats = ctx->inputs[i]->in_formats;
88 avfilter_formats_ref(formats, &ctx->inputs[i]->out_formats);
89 avfilter_formats_ref(formats, &ctx->outputs[i]->in_formats);
90 layouts = ctx->inputs[i]->in_channel_layouts;
91 ff_channel_layouts_ref(layouts, &ctx->inputs[i]->out_channel_layouts);
92 ff_channel_layouts_ref(layouts, &ctx->outputs[i]->in_channel_layouts);
97 static int config_output(AVFilterLink *outlink)
99 AVFilterContext *ctx = outlink->src;
100 int id = outlink == ctx->outputs[1];
102 outlink->sample_rate = ctx->inputs[id]->sample_rate;
103 outlink->time_base = ctx->inputs[id]->time_base;
107 static void send_out(AVFilterContext *ctx, int out_id)
109 AStreamSyncContext *as = ctx->priv;
110 struct buf_queue *queue = &as->queue[out_id];
111 AVFilterBufferRef *buf = queue->buf[queue->tail];
113 queue->buf[queue->tail] = NULL;
114 as->var_values[VAR_B1 + out_id]++;
115 as->var_values[VAR_S1 + out_id] += buf->audio->nb_samples;
116 if (buf->pts != AV_NOPTS_VALUE)
117 as->var_values[VAR_T1 + out_id] =
118 av_q2d(ctx->outputs[out_id]->time_base) * buf->pts;
119 as->var_values[VAR_T1 + out_id] += buf->audio->nb_samples /
120 (double)ctx->inputs[out_id]->sample_rate;
121 ff_filter_samples(ctx->outputs[out_id], buf);
123 queue->tail = (queue->tail + 1) % QUEUE_SIZE;
128 static void send_next(AVFilterContext *ctx)
130 AStreamSyncContext *as = ctx->priv;
134 if (!as->queue[as->next_out].nb)
136 send_out(ctx, as->next_out);
138 as->next_out = av_expr_eval(as->expr, as->var_values, NULL) >= 0;
140 for (i = 0; i < 2; i++)
141 if (as->queue[i].nb == QUEUE_SIZE)
145 static int request_frame(AVFilterLink *outlink)
147 AVFilterContext *ctx = outlink->src;
148 AStreamSyncContext *as = ctx->priv;
149 int id = outlink == ctx->outputs[1];
152 while (as->req[id] && !(as->eof & (1 << id))) {
153 if (as->queue[as->next_out].nb) {
156 as->eof |= 1 << as->next_out;
157 avfilter_request_frame(ctx->inputs[as->next_out]);
158 if (as->eof & (1 << as->next_out))
159 as->next_out = !as->next_out;
165 static void filter_samples(AVFilterLink *inlink, AVFilterBufferRef *insamples)
167 AVFilterContext *ctx = inlink->dst;
168 AStreamSyncContext *as = ctx->priv;
169 int id = inlink == ctx->inputs[1];
171 as->queue[id].buf[(as->queue[id].tail + as->queue[id].nb++) % QUEUE_SIZE] =
173 as->eof &= ~(1 << id);
177 AVFilter avfilter_af_astreamsync = {
178 .name = "astreamsync",
179 .description = NULL_IF_CONFIG_SMALL("Copy two streams of audio data "
180 "in a configurable order."),
181 .priv_size = sizeof(AStreamSyncContext),
183 .query_formats = query_formats,
185 .inputs = (const AVFilterPad[]) {
187 .type = AVMEDIA_TYPE_AUDIO,
188 .filter_samples = filter_samples,
189 .min_perms = AV_PERM_READ, },
191 .type = AVMEDIA_TYPE_AUDIO,
192 .filter_samples = filter_samples,
193 .min_perms = AV_PERM_READ, },
196 .outputs = (const AVFilterPad[]) {
198 .type = AVMEDIA_TYPE_AUDIO,
199 .config_props = config_output,
200 .request_frame = request_frame, },
202 .type = AVMEDIA_TYPE_AUDIO,
203 .config_props = config_output,
204 .request_frame = request_frame, },