From 1491fa81f4ccdc330a5f99300ec62bf369b4bf5e Mon Sep 17 00:00:00 2001
From: Jean-Marc Valin <jmvalin@jmvalin.ca>
Date: Mon, 10 Sep 2012 16:24:33 -0400
Subject: [PATCH] Fixes to the new repacketizer doc
---
include/opus.h | 29 ++++++++++++++++++++---------
1 file changed, 20 insertions(+), 9 deletions(-)
diff --git a/include/opus.h b/include/opus.h
index 9de31af64..abce5c713 100644
--- a/include/opus.h
+++ b/include/opus.h
@@ -525,7 +525,11 @@ OPUS_EXPORT OPUS_WARN_UNUSED_RESULT int opus_decoder_get_nb_samples(const OpusDe
*
* The repacketizer can be used to merge multiple Opus packets into a single
* packet or alternatively to split Opus packets that have previously been
- * merged. The repacketizer currently only operates on elementary Opus
+ * merged. Splitting valid Opus packets is always guaranteed to succeed,
+ * whereas merging valid packets only succeeds if all frames have the same
+ * mode, bandwidth, and frame size, and when the total duration of the merged
+ * packet is no more than 120 ms.
+ * The repacketizer currently only operates on elementary Opus
* streams. It will not manipualte multistream packets successfully, except in
* the degenerate case where they consist of data from a single stream.
*
@@ -581,12 +585,12 @@ OPUS_EXPORT OPUS_WARN_UNUSED_RESULT int opus_decoder_get_nb_samples(const OpusDe
* contain up to <code>TARGET_DURATION_MS</code> milliseconds of data:
* @code
* // The maximum number of packets with duration TARGET_DURATION_MS occurs
- * // when the frame size is 2.5 ms, for a total of (TARGET_DURATION_MS*5/2)
+ * // when the frame size is 2.5 ms, for a total of (TARGET_DURATION_MS*2/5)
* // packets.
- * unsigned char *data[(TARGET_DURATION_MS*5/2)+1];
- * opus_int32 len[(TARGET_DURATION_MS*5/2)+1];
+ * unsigned char *data[(TARGET_DURATION_MS*2/5)+1];
+ * opus_int32 len[(TARGET_DURATION_MS*2/5)+1];
* int nb_packets;
- * unsigned char out[1277*(TARGET_DURATION_MS*5/2)];
+ * unsigned char out[1277*(TARGET_DURATION_MS*2/2)];
* opus_int32 out_len;
* int prev_toc;
* nb_packets = 0;
@@ -613,8 +617,8 @@ OPUS_EXPORT OPUS_WARN_UNUSED_RESULT int opus_decoder_get_nb_samples(const OpusDe
* // reference to data[nb_packets][0] should be valid.
* if (nb_packets > 0 && (
* ((prev_toc & 0xFC) != (data[nb_packets][0] & 0xFC)) ||
- * opus_packet_get_samples_per_frame(data[nb_packets], 2000)*nb_frames >
- * TARGET_DURATION_MS*2))
+ * opus_packet_get_samples_per_frame(data[nb_packets], 48000)*nb_frames >
+ * TARGET_DURATION_MS*48))
* {
* out_len = opus_repacketizer_out(rp, out, sizeof(out));
* if (out_len < 0)
@@ -648,6 +652,12 @@ OPUS_EXPORT OPUS_WARN_UNUSED_RESULT int opus_decoder_get_nb_samples(const OpusDe
* output_next_packet(out, out_len);
* }
* @endcode
+ *
+ * An alternate way of merging packets is to simply call opus_repacketizer_cat()
+ * unconditionally until it fails. At that point, the merged packet can be
+ * obtained with opus_repacketizer_out() and the input packet for which
+ * opus_repacketizer_cat() needs to be re-added to a newly reinitialized
+ * repacketizer state.
*/
typedef struct OpusRepacketizer OpusRepacketizer;
@@ -658,7 +668,7 @@ typedef struct OpusRepacketizer OpusRepacketizer;
OPUS_EXPORT OPUS_WARN_UNUSED_RESULT int opus_repacketizer_get_size(void);
/** (Re)initializes a previously allocated repacketizer state.
- * The state must be the size returned by opus_repacketizer_get_size().
+ * The state must be at least the size returned by opus_repacketizer_get_size().
* This can be used for applications which use their own allocator instead of
* malloc().
* It must also be called to reset the queue of packets waiting to be
@@ -676,7 +686,8 @@ OPUS_EXPORT OPUS_WARN_UNUSED_RESULT int opus_repacketizer_get_size(void);
*/
OPUS_EXPORT OpusRepacketizer *opus_repacketizer_init(OpusRepacketizer *rp) OPUS_ARG_NONNULL(1);
-/** Allocates and initializes a repacketizer state.
+/** Allocates memory and initializes the new repacketizer with
+ * opus_repacketizer_init().
*/
OPUS_EXPORT OPUS_WARN_UNUSED_RESULT OpusRepacketizer *opus_repacketizer_create(void);
--
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