From: Luca Barbato <[email protected]>
Useful in cases where a significant analyzeduration is
still needed, while minimizing buffering before output.
An example is processing low-latency streams where all
media types won't necessarily come in if the
analyzeduration is small.
---
Updated against latest libav, adjusted naming, set
the nobuffer flag to 0x0040, clarified commit message.
libavformat/avformat.h | 1 +
libavformat/options_table.h | 1 +
libavformat/utils.c | 11 ++++++++---
3 files changed, 10 insertions(+), 3 deletions(-)
diff --git a/libavformat/avformat.h b/libavformat/avformat.h
index e292206..7c97ada 100644
--- a/libavformat/avformat.h
+++ b/libavformat/avformat.h
@@ -887,6 +887,7 @@ typedef struct AVFormatContext {
#define AVFMT_FLAG_IGNDTS 0x0008 ///< Ignore DTS on frames that contain
both DTS & PTS
#define AVFMT_FLAG_NOFILLIN 0x0010 ///< Do not infer any values from other
values, just return what is stored in the container
#define AVFMT_FLAG_NOPARSE 0x0020 ///< Do not use AVParsers, you also
must set AVFMT_FLAG_NOFILLIN as the fillin code works on frames and no parsing
-> no frames. Also seeking to frames can not work if parsing to find frame
boundaries has been disabled
+#define AVFMT_FLAG_NOBUFFER 0x0040 ///< Do not buffer frames when possible
#define AVFMT_FLAG_CUSTOM_IO 0x0080 ///< The caller has supplied a custom
AVIOContext, don't avio_close() it.
#define AVFMT_FLAG_DISCARD_CORRUPT 0x0100 ///< Discard frames marked corrupted
diff --git a/libavformat/options_table.h b/libavformat/options_table.h
index 58f3dcf..f3384ca 100644
--- a/libavformat/options_table.h
+++ b/libavformat/options_table.h
@@ -40,6 +40,7 @@ static const AVOption options[]={
{"noparse", "disable AVParsers, this needs nofillin too", 0,
AV_OPT_TYPE_CONST, {.dbl = AVFMT_FLAG_NOPARSE }, INT_MIN, INT_MAX, D, "fflags"},
{"igndts", "ignore dts", 0, AV_OPT_TYPE_CONST, {.dbl = AVFMT_FLAG_IGNDTS },
INT_MIN, INT_MAX, D, "fflags"},
{"discardcorrupt", "discard corrupted frames", 0, AV_OPT_TYPE_CONST, {.dbl =
AVFMT_FLAG_DISCARD_CORRUPT }, INT_MIN, INT_MAX, D, "fflags"},
+{"nobuffer", "reduce the latency introduced by optional buffering", 0,
AV_OPT_TYPE_CONST, {.dbl = AVFMT_FLAG_NOBUFFER }, 0, INT_MAX, D, "fflags"},
{"analyzeduration", "how many microseconds are analyzed to estimate duration",
OFFSET(max_analyze_duration), AV_OPT_TYPE_INT, {.dbl = 5*AV_TIME_BASE }, 0,
INT_MAX, D},
{"cryptokey", "decryption key", OFFSET(key), AV_OPT_TYPE_BINARY, {.dbl = 0},
0, 0, D},
{"indexmem", "max memory used for timestamp index (per stream)",
OFFSET(max_index_size), AV_OPT_TYPE_INT, {.dbl = 1<<20 }, 0, INT_MAX, D},
diff --git a/libavformat/utils.c b/libavformat/utils.c
index 156c527..fd92bc4 100644
--- a/libavformat/utils.c
+++ b/libavformat/utils.c
@@ -2382,9 +2382,14 @@ int avformat_find_stream_info(AVFormatContext *ic,
AVDictionary **options)
break;
}
- pkt= add_to_pktbuf(&ic->packet_buffer, &pkt1, &ic->packet_buffer_end);
- if ((ret = av_dup_packet(pkt)) < 0)
- goto find_stream_info_err;
+ if (ic->flags & AVFMT_FLAG_NOBUFFER) {
+ pkt = &pkt1;
+ } else {
+ pkt = add_to_pktbuf(&ic->packet_buffer, &pkt1,
+ &ic->packet_buffer_end);
+ if ((ret = av_dup_packet(pkt)) < 0)
+ goto find_stream_info_err;
+ }
read_size += pkt->size;
--
1.7.9.5
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