[FFmpeg-devel,3/4] avformat: make flush_packets a tri-state and set it to -1 (auto) by default

Submitted by Marton Balint on June 18, 2017, 10:02 p.m.

Details

Message ID 20170618220254.21682-3-cus@passwd.hu
State Superseded
Headers show

Commit Message

Marton Balint June 18, 2017, 10:02 p.m.
If flushing is not disabled, then mux.c will signal the end of the packets with
an AVIO_DATA_MARKER_FLUSH_POINT, and aviobuf will be able to decide to flush or
not based on the preferred minimum packet size set by the used protocol.

Signed-off-by: Marton Balint <cus@passwd.hu>
---
 doc/formats.texi            |  7 ++++---
 libavformat/mux.c           | 12 +++++++++---
 libavformat/options_table.h |  4 ++--
 3 files changed, 15 insertions(+), 8 deletions(-)

Comments

Michael Niedermayer June 19, 2017, 3:21 p.m.
On Mon, Jun 19, 2017 at 12:02:53AM +0200, Marton Balint wrote:
> If flushing is not disabled, then mux.c will signal the end of the packets with
> an AVIO_DATA_MARKER_FLUSH_POINT, and aviobuf will be able to decide to flush or
> not based on the preferred minimum packet size set by the used protocol.
> 
> Signed-off-by: Marton Balint <cus@passwd.hu>
> ---
>  doc/formats.texi            |  7 ++++---
>  libavformat/mux.c           | 12 +++++++++---
>  libavformat/options_table.h |  4 ++--
>  3 files changed, 15 insertions(+), 8 deletions(-)
> 
> diff --git a/doc/formats.texi b/doc/formats.texi
> index c51d4086db..ddd7743548 100644
> --- a/doc/formats.texi
> +++ b/doc/formats.texi
> @@ -182,9 +182,10 @@ Default is 0.
>  Correct single timestamp overflows if set to 1. Default is 1.
>  
>  @item flush_packets @var{integer} (@emph{output})
> -Flush the underlying I/O stream after each packet. Default 1 enables it, and
> -has the effect of reducing the latency; 0 disables it and may slightly
> -increase performance in some cases.
> +Flush the underlying I/O stream after each packet. Default is -1 (auto), which
> +means that the underlying protocol will decide, 1 enables it, and has the
> +effect of reducing the latency, 0 disables it and may increase IO throughput in
> +some cases.
>  
>  @item output_ts_offset @var{offset} (@emph{output})
>  Set the output time offset.
> diff --git a/libavformat/mux.c b/libavformat/mux.c
> index e1e49a81be..7c97b77881 100644
> --- a/libavformat/mux.c
> +++ b/libavformat/mux.c
> @@ -479,8 +479,10 @@ static int write_header_internal(AVFormatContext *s)
>          s->internal->write_header_ret = ret;
>          if (ret < 0)
>              return ret;
> -        if (s->flush_packets && s->pb && s->pb->error >= 0 && s->flags & AVFMT_FLAG_FLUSH_PACKETS)
> +        if ((s->flush_packets == 1 || s->flags & AVFMT_FLAG_FLUSH_PACKETS) && s->pb && s->pb->error >= 0)
>              avio_flush(s->pb);
> +        if (s->flush_packets && !(s->oformat->flags & AVFMT_NOFILE) && s->pb && s->pb->error >= 0)
> +            avio_write_marker(s->pb, AV_NOPTS_VALUE, AVIO_DATA_MARKER_FLUSH_POINT);


[...]
>      if (s->pb && ret >= 0) {
> -        if (s->flush_packets && s->flags & AVFMT_FLAG_FLUSH_PACKETS)
> +        if (s->flush_packets == 1 || s->flags & AVFMT_FLAG_FLUSH_PACKETS)
>              avio_flush(s->pb);
> +        if (s->flush_packets && !(s->oformat->flags & AVFMT_NOFILE))
> +            avio_write_marker(s->pb, AV_NOPTS_VALUE, AVIO_DATA_MARKER_FLUSH_POINT);

are these inteded to be if() instead of else if() ?

Either way iam in favor of this patch

thx

[...]
Marton Balint June 19, 2017, 9:13 p.m.
On Mon, 19 Jun 2017, Michael Niedermayer wrote:

> On Mon, Jun 19, 2017 at 12:02:53AM +0200, Marton Balint wrote:
>> If flushing is not disabled, then mux.c will signal the end of the packets with
>> an AVIO_DATA_MARKER_FLUSH_POINT, and aviobuf will be able to decide to flush or
>> not based on the preferred minimum packet size set by the used protocol.
>>
>> Signed-off-by: Marton Balint <cus@passwd.hu>
>> ---
>>  doc/formats.texi            |  7 ++++---
>>  libavformat/mux.c           | 12 +++++++++---
>>  libavformat/options_table.h |  4 ++--
>>  3 files changed, 15 insertions(+), 8 deletions(-)
>>
>> diff --git a/doc/formats.texi b/doc/formats.texi
>> index c51d4086db..ddd7743548 100644
>> --- a/doc/formats.texi
>> +++ b/doc/formats.texi
>> @@ -182,9 +182,10 @@ Default is 0.
>>  Correct single timestamp overflows if set to 1. Default is 1.
>>
>>  @item flush_packets @var{integer} (@emph{output})
>> -Flush the underlying I/O stream after each packet. Default 1 enables it, and
>> -has the effect of reducing the latency; 0 disables it and may slightly
>> -increase performance in some cases.
>> +Flush the underlying I/O stream after each packet. Default is -1 (auto), which
>> +means that the underlying protocol will decide, 1 enables it, and has the
>> +effect of reducing the latency, 0 disables it and may increase IO throughput in
>> +some cases.
>>
>>  @item output_ts_offset @var{offset} (@emph{output})
>>  Set the output time offset.
>> diff --git a/libavformat/mux.c b/libavformat/mux.c
>> index e1e49a81be..7c97b77881 100644
>> --- a/libavformat/mux.c
>> +++ b/libavformat/mux.c
>> @@ -479,8 +479,10 @@ static int write_header_internal(AVFormatContext *s)
>>          s->internal->write_header_ret = ret;
>>          if (ret < 0)
>>              return ret;
>> -        if (s->flush_packets && s->pb && s->pb->error >= 0 && s->flags & AVFMT_FLAG_FLUSH_PACKETS)
>> +        if ((s->flush_packets == 1 || s->flags & AVFMT_FLAG_FLUSH_PACKETS) && s->pb && s->pb->error >= 0)
>>              avio_flush(s->pb);
>> +        if (s->flush_packets && !(s->oformat->flags & AVFMT_NOFILE) && s->pb && s->pb->error >= 0)
>> +            avio_write_marker(s->pb, AV_NOPTS_VALUE, AVIO_DATA_MARKER_FLUSH_POINT);
>
>
> [...]
>>      if (s->pb && ret >= 0) {
>> -        if (s->flush_packets && s->flags & AVFMT_FLAG_FLUSH_PACKETS)
>> +        if (s->flush_packets == 1 || s->flags & AVFMT_FLAG_FLUSH_PACKETS)
>>              avio_flush(s->pb);
>> +        if (s->flush_packets && !(s->oformat->flags & AVFMT_NOFILE))
>> +            avio_write_marker(s->pb, AV_NOPTS_VALUE, AVIO_DATA_MARKER_FLUSH_POINT);
>
> are these inteded to be if() instead of else if() ?

It does not really make a difference in the current code, I will change it 
to else if.

>
> Either way iam in favor of this patch
>

Great, thanks.

Regards,
Marton

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diff --git a/doc/formats.texi b/doc/formats.texi
index c51d4086db..ddd7743548 100644
--- a/doc/formats.texi
+++ b/doc/formats.texi
@@ -182,9 +182,10 @@  Default is 0.
 Correct single timestamp overflows if set to 1. Default is 1.
 
 @item flush_packets @var{integer} (@emph{output})
-Flush the underlying I/O stream after each packet. Default 1 enables it, and
-has the effect of reducing the latency; 0 disables it and may slightly
-increase performance in some cases.
+Flush the underlying I/O stream after each packet. Default is -1 (auto), which
+means that the underlying protocol will decide, 1 enables it, and has the
+effect of reducing the latency, 0 disables it and may increase IO throughput in
+some cases.
 
 @item output_ts_offset @var{offset} (@emph{output})
 Set the output time offset.
diff --git a/libavformat/mux.c b/libavformat/mux.c
index e1e49a81be..7c97b77881 100644
--- a/libavformat/mux.c
+++ b/libavformat/mux.c
@@ -479,8 +479,10 @@  static int write_header_internal(AVFormatContext *s)
         s->internal->write_header_ret = ret;
         if (ret < 0)
             return ret;
-        if (s->flush_packets && s->pb && s->pb->error >= 0 && s->flags & AVFMT_FLAG_FLUSH_PACKETS)
+        if ((s->flush_packets == 1 || s->flags & AVFMT_FLAG_FLUSH_PACKETS) && s->pb && s->pb->error >= 0)
             avio_flush(s->pb);
+        if (s->flush_packets && !(s->oformat->flags & AVFMT_NOFILE) && s->pb && s->pb->error >= 0)
+            avio_write_marker(s->pb, AV_NOPTS_VALUE, AVIO_DATA_MARKER_FLUSH_POINT);
     }
     s->internal->header_written = 1;
     if (!(s->oformat->flags & AVFMT_NOFILE) && s->pb)
@@ -772,8 +774,10 @@  FF_ENABLE_DEPRECATION_WARNINGS
     }
 
     if (s->pb && ret >= 0) {
-        if (s->flush_packets && s->flags & AVFMT_FLAG_FLUSH_PACKETS)
+        if (s->flush_packets == 1 || s->flags & AVFMT_FLAG_FLUSH_PACKETS)
             avio_flush(s->pb);
+        if (s->flush_packets && !(s->oformat->flags & AVFMT_NOFILE))
+            avio_write_marker(s->pb, AV_NOPTS_VALUE, AVIO_DATA_MARKER_FLUSH_POINT);
         if (s->pb->error < 0)
             ret = s->pb->error;
     }
@@ -932,8 +936,10 @@  int av_write_frame(AVFormatContext *s, AVPacket *pkt)
                     return ret;
             }
             ret = s->oformat->write_packet(s, NULL);
-            if (s->flush_packets && s->pb && s->pb->error >= 0 && s->flags & AVFMT_FLAG_FLUSH_PACKETS)
+            if ((s->flush_packets == 1 || s->flags & AVFMT_FLAG_FLUSH_PACKETS) && s->pb && s->pb->error >= 0)
                 avio_flush(s->pb);
+            if (s->flush_packets && !(s->oformat->flags & AVFMT_NOFILE) && s->pb && s->pb->error >= 0)
+                avio_write_marker(s->pb, AV_NOPTS_VALUE, AVIO_DATA_MARKER_FLUSH_POINT);
             if (ret >= 0 && s->pb && s->pb->error < 0)
                 ret = s->pb->error;
             return ret;
diff --git a/libavformat/options_table.h b/libavformat/options_table.h
index 0c1915d6d4..118086df66 100644
--- a/libavformat/options_table.h
+++ b/libavformat/options_table.h
@@ -39,7 +39,7 @@  static const AVOption avformat_options[] = {
 {"probesize", "set probing size", OFFSET(probesize), AV_OPT_TYPE_INT64, {.i64 = 5000000 }, 32, INT64_MAX, D},
 {"formatprobesize", "number of bytes to probe file format", OFFSET(format_probesize), AV_OPT_TYPE_INT, {.i64 = PROBE_BUF_MAX}, 0, INT_MAX-1, D},
 {"packetsize", "set packet size", OFFSET(packet_size), AV_OPT_TYPE_INT, {.i64 = DEFAULT }, 0, INT_MAX, E},
-{"fflags", NULL, OFFSET(flags), AV_OPT_TYPE_FLAGS, {.i64 = AVFMT_FLAG_FLUSH_PACKETS | AVFMT_FLAG_AUTO_BSF }, INT_MIN, INT_MAX, D|E, "fflags"},
+{"fflags", NULL, OFFSET(flags), AV_OPT_TYPE_FLAGS, {.i64 = AVFMT_FLAG_AUTO_BSF }, INT_MIN, INT_MAX, D|E, "fflags"},
 {"flush_packets", "reduce the latency by flushing out packets immediately", 0, AV_OPT_TYPE_CONST, {.i64 = AVFMT_FLAG_FLUSH_PACKETS }, INT_MIN, INT_MAX, E, "fflags"},
 {"ignidx", "ignore index", 0, AV_OPT_TYPE_CONST, {.i64 = AVFMT_FLAG_IGNIDX }, INT_MIN, INT_MAX, D, "fflags"},
 {"genpts", "generate pts", 0, AV_OPT_TYPE_CONST, {.i64 = AVFMT_FLAG_GENPTS }, INT_MIN, INT_MAX, D, "fflags"},
@@ -85,7 +85,7 @@  static const AVOption avformat_options[] = {
 {"use_wallclock_as_timestamps", "use wallclock as timestamps", OFFSET(use_wallclock_as_timestamps), AV_OPT_TYPE_BOOL, {.i64 = 0}, 0, 1, D},
 {"skip_initial_bytes", "set number of bytes to skip before reading header and frames", OFFSET(skip_initial_bytes), AV_OPT_TYPE_INT64, {.i64 = 0}, 0, INT64_MAX-1, D},
 {"correct_ts_overflow", "correct single timestamp overflows", OFFSET(correct_ts_overflow), AV_OPT_TYPE_BOOL, {.i64 = 1}, 0, 1, D},
-{"flush_packets", "enable flushing of the I/O context after each packet", OFFSET(flush_packets), AV_OPT_TYPE_BOOL, {.i64 = 1}, 0, 1, E},
+{"flush_packets", "enable flushing of the I/O context after each packet", OFFSET(flush_packets), AV_OPT_TYPE_INT, {.i64 = -1}, -1, 1, E},
 {"metadata_header_padding", "set number of bytes to be written as padding in a metadata header", OFFSET(metadata_header_padding), AV_OPT_TYPE_INT, {.i64 = -1}, -1, INT_MAX, E},
 {"output_ts_offset", "set output timestamp offset", OFFSET(output_ts_offset), AV_OPT_TYPE_DURATION, {.i64 = 0}, -INT64_MAX, INT64_MAX, E},
 {"max_interleave_delta", "maximum buffering duration for interleaving", OFFSET(max_interleave_delta), AV_OPT_TYPE_INT64, { .i64 = 10000000 }, 0, INT64_MAX, E },