| Message ID | 98e50dd9-c85e-3f18-654c-228ea6cb8113@davyandbeth.com |
|---|---|
| State | New |
| Headers | show |
| Series | [FFmpeg-devel] fftools/ffmpeg: Added ability to set a input burst time before readrate is enforced | expand |
| Context | Check | Description |
|---|---|---|
| yinshiyou/configure_loongarch64 | warning | Failed to apply patch |
| andriy/configure_x86 | warning | Failed to apply patch |
Your email client mangled the patch, so it cannot be applied as is. Quoting Davy Durham (2023-04-07 09:57:54) > Implemented is the -irb <seconds> flag (i.e. "initial read burst") that > causes ffmpeg to read the specified number of seconds of input before a > given readrate starts to be enforced. All inputs have to reach this > point before the readrate is enforced. The reason for this change is, > in the scenario of live-streaming by transcoding from an pre-recorded or > delayed source to an HLS or DASH webroot, we can more quickly prime the > system of the first few seconds before the real-world read rate is > imposed. Else, one must wait for an entire segment length before the > data can be fetched from the web server. > > Signed-off-by: Davy Durham <ddurham@users.sourceforge.net> > --- > doc/ffmpeg.texi | 2 ++ > fftools/ffmpeg.h | 2 ++ > fftools/ffmpeg_demux.c | 13 ++++++++++++- > fftools/ffmpeg_opt.c | 3 +++ > 4 files changed, 19 insertions(+), 1 deletion(-) > > diff --git a/doc/ffmpeg.texi b/doc/ffmpeg.texi > index d433d60ce9..a519fea192 100644 > --- a/doc/ffmpeg.texi > +++ b/doc/ffmpeg.texi > @@ -1709,6 +1709,8 @@ it may cause packet loss. > It is useful for when flow speed of output packets is important, such > as live streaming. > @item -re (@emph{input}) > Read input at native frame rate. This is equivalent to setting > @code{-readrate 1}. > +@item -irb @var{seconds} I think 'irb' is too short for an option that modifies behavior of another, rather obscure, option. How about -readrate_burst or -readrate_delay or something along these lines? > @@ -1159,6 +1160,16 @@ int ifile_open(const OptionsContext *o, const > char *filename) > f->rate_emu = 0; > } > + f->initial_read_burst = o->initial_read_burst ? > o->initial_read_burst : 0.0; > + if (f->initial_read_burst < 0.0) { > + av_log(NULL, AV_LOG_ERROR, "Option -irb for Input #%d is %0.3f; Use f as the log context, then you can drop the input file number in the string itself. Same below. Otherwise seems reasonable.
diff --git a/doc/ffmpeg.texi b/doc/ffmpeg.texi index d433d60ce9..a519fea192 100644 --- a/doc/ffmpeg.texi +++ b/doc/ffmpeg.texi @@ -1709,6 +1709,8 @@ it may cause packet loss. It is useful for when flow speed of output packets is important, such as live streaming. @item -re (@emph{input}) Read input at native frame rate. This is equivalent to setting @code{-readrate 1}. +@item -irb @var{seconds} +Set an initial read burst time, in seconds, after which any specified readrate will be enforced. @item -vsync @var{parameter} (@emph{global}) @itemx -fps_mode[:@var{stream_specifier}] @var{parameter} (@emph{output,per-stream}) Set video sync method / framerate mode. vsync is applied to all output video streams diff --git a/fftools/ffmpeg.h b/fftools/ffmpeg.h index 823218e214..e057e6da3a 100644 --- a/fftools/ffmpeg.h +++ b/fftools/ffmpeg.h @@ -124,6 +124,7 @@ typedef struct OptionsContext { int loop; int rate_emu; float readrate; + double initial_read_burst; int accurate_seek; int thread_queue_size; int input_sync_ref; @@ -475,6 +476,7 @@ typedef struct InputFile { int rate_emu; float readrate; + double initial_read_burst; int accurate_seek; /* when looping the input file, this queue is used by decoders to report diff --git a/fftools/ffmpeg_demux.c b/fftools/ffmpeg_demux.c index db05ddb8e9..af423c9be4 100644 --- a/fftools/ffmpeg_demux.c +++ b/fftools/ffmpeg_demux.c @@ -453,6 +453,7 @@ int ifile_get_packet(InputFile *f, AVPacket **pkt) (f->start_time != AV_NOPTS_VALUE ? f->start_time : 0) ); float scale = f->rate_emu ? 1.0 : f->readrate; + int64_t burst_until = AV_TIME_BASE * f->initial_read_burst; for (i = 0; i < f->nb_streams; i++) { InputStream *ist = f->streams[i]; int64_t stream_ts_offset, pts, now; @@ -460,7 +461,7 @@ int ifile_get_packet(InputFile *f, AVPacket **pkt) stream_ts_offset = FFMAX(ist->first_dts != AV_NOPTS_VALUE ? ist->first_dts : 0, file_start); pts = av_rescale(ist->dts, 1000000, AV_TIME_BASE); now = (av_gettime_relative() - ist->start) * scale + stream_ts_offset; - if (pts > now) + if (pts - burst_until > now) return AVERROR(EAGAIN); } } @@ -1159,6 +1160,16 @@ int ifile_open(const OptionsContext *o, const char *filename) f->rate_emu = 0; } + f->initial_read_burst = o->initial_read_burst ? o->initial_read_burst : 0.0; + if (f->initial_read_burst < 0.0) { + av_log(NULL, AV_LOG_ERROR, "Option -irb for Input #%d is %0.3f; it must be non-negative.\n", nb_input_files, f->initial_read_burst); + exit_program(1); + } + if ((!f->readrate && !f->rate_emu) && f->initial_read_burst) { + av_log(NULL, AV_LOG_WARNING, "Option -irb ignored since neither -readrate nor -re were given\n"); + f->initial_read_burst = 0; + } + d->thread_queue_size = o->thread_queue_size; /* update the current parameters so that they match the one of the input stream */ diff --git a/fftools/ffmpeg_opt.c b/fftools/ffmpeg_opt.c index 055275d813..6c55b6cb01 100644 --- a/fftools/ffmpeg_opt.c +++ b/fftools/ffmpeg_opt.c @@ -1443,6 +1443,9 @@ const OptionDef options[] = { { "readrate", HAS_ARG | OPT_FLOAT | OPT_OFFSET | OPT_EXPERT | OPT_INPUT, { .off = OFFSET(readrate) }, "read input at specified rate", "speed" }, + { "irb", HAS_ARG | OPT_DOUBLE | OPT_OFFSET | + OPT_EXPERT | OPT_INPUT, { .off = OFFSET(initial_read_burst) }, + "The initial amount of input to burst read before imposing any readrate", "seconds" },
Implemented is the -irb <seconds> flag (i.e. "initial read burst") that causes ffmpeg to read the specified number of seconds of input before a given readrate starts to be enforced. All inputs have to reach this point before the readrate is enforced. The reason for this change is, in the scenario of live-streaming by transcoding from an pre-recorded or delayed source to an HLS or DASH webroot, we can more quickly prime the system of the first few seconds before the real-world read rate is imposed. Else, one must wait for an entire segment length before the data can be fetched from the web server. Signed-off-by: Davy Durham <ddurham@users.sourceforge.net> --- doc/ffmpeg.texi | 2 ++ fftools/ffmpeg.h | 2 ++ fftools/ffmpeg_demux.c | 13 ++++++++++++- fftools/ffmpeg_opt.c | 3 +++ 4 files changed, 19 insertions(+), 1 deletion(-) { "target", HAS_ARG | OPT_PERFILE | OPT_OUTPUT, { .func_arg = opt_target }, "specify target file type (\"vcd\", \"svcd\", \"dvd\", \"dv\" or \"dv50\" " "with optional prefixes \"pal-\", \"ntsc-\" or \"film-\")", "type" },