avcodec: add code for a frame queue for use by audio encoders with delay

This simplifies matching of timestamps between input frames and output
packets.

1 files changed, 90 insertions, 0 deletions

diff --git a/libavcodec/audio_frame_queue.h b/libavcodec/audio_frame_queue.h
new file mode 100644
index 0000000000..cfcc6a030c
--- /dev/null
+++ b/libavcodec/audio_frame_queue.h
@@ -0,0 +1,90 @@
+/*
+ * Audio Frame Queue
+ * Copyright (c) 2012 Justin Ruggles
+ *
+ * This file is part of Libav.
+ *
+ * Libav is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * Libav 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
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with Libav; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#ifndef AVCODEC_AUDIO_FRAME_QUEUE_H
+#define AVCODEC_AUDIO_FRAME_QUEUE_H
+
+#include "avcodec.h"
+
+typedef struct AudioFrame {
+    int64_t pts;
+    int duration;
+    struct AudioFrame *next;
+} AudioFrame;
+
+typedef struct AudioFrameQueue {
+    AVCodecContext *avctx;
+    int64_t next_pts;
+    int remaining_delay;
+    int remaining_samples;
+    AudioFrame *frame_queue;
+} AudioFrameQueue;
+
+/**
+ * Initialize AudioFrameQueue.
+ *
+ * @param avctx context to use for time_base and av_log
+ * @param afq   queue context
+ */
+void ff_af_queue_init(AVCodecContext *avctx, AudioFrameQueue *afq);
+
+/**
+ * Close AudioFrameQueue.
+ *
+ * Frees memory if needed.
+ *
+ * @param afq queue context
+ */
+void ff_af_queue_close(AudioFrameQueue *afq);
+
+/**
+ * Add a frame to the queue.
+ *
+ * @param afq queue context
+ * @param f   frame to add to the queue
+ */
+int ff_af_queue_add(AudioFrameQueue *afq, const AVFrame *f);
+
+/**
+ * Remove frame(s) from the queue.
+ *
+ * Retrieves the pts of the next available frame, or a generated pts based on
+ * the last frame duration if there are no frames left in the queue. The number
+ * of requested samples should be the full number of samples represented by the
+ * packet that will be output by the encoder. If fewer samples are available
+ * in the queue, a smaller value will be used for the output duration.
+ *
+ * @param afq           queue context
+ * @param nb_samples    number of samples to remove from the queue
+ * @param[out] pts      output packet pts
+ * @param[out] duration output packet duration
+ */
+void ff_af_queue_remove(AudioFrameQueue *afq, int nb_samples, int64_t *pts,
+                        int *duration);
+
+/**
+ * Log the current state of the queue.
+ *
+ * @param afq queue context
+ */
+void ff_af_queue_log_state(AudioFrameQueue *afq);
+
+#endif /* AVCODEC_AUDIO_FRAME_QUEUE_H */