[FFmpeg-devel] [PATCH v2] lavf/img2enc: add support for option strftime_start_realtime

[Jun Li]

On Thu, Apr 18, 2019 at 5:59 PM Jun Li <junli1026 at gmail.com> wrote:

> Currently the strftime option generate timestamp based on generation
> time. The new option would calcualte timestamp from start_time_realtime
> and pkt->pts, based on output's timescale.
> ---
>  doc/muxers.texi       |  5 +++++
>  libavformat/img2enc.c | 34 ++++++++++++++++++++++++++++++++++
>  2 files changed, 39 insertions(+)
>
> diff --git a/doc/muxers.texi b/doc/muxers.texi
> index 83ae017d6c..ee99ef621e 100644
> --- a/doc/muxers.texi
> +++ b/doc/muxers.texi
> @@ -1193,6 +1193,11 @@ overwritten with new images. Default value is 0.
>  @item strftime
>  If set to 1, expand the filename with date and time information from
>  @code{strftime()}. Default value is 0.
> +
> + at item strftime_start_realtime
> +If set to 1, expand the filename with date and time information from
> + at code{strftime()}, starting from start_time_realtime and calcualted
> +from pkt->pts in UTC time. Default value is 0.
>  @end table
>
>  The image muxer supports the .Y.U.V image file format. This format is
> diff --git a/libavformat/img2enc.c b/libavformat/img2enc.c
> index bec4bf81dd..0f27e5ceaf 100644
> --- a/libavformat/img2enc.c
> +++ b/libavformat/img2enc.c
> @@ -26,6 +26,7 @@
>  #include "libavutil/log.h"
>  #include "libavutil/opt.h"
>  #include "libavutil/pixdesc.h"
> +#include "libavutil/time.h"
>  #include "libavutil/time_internal.h"
>  #include "avformat.h"
>  #include "avio_internal.h"
> @@ -45,6 +46,7 @@ typedef struct VideoMuxData {
>      int frame_pts;
>      const char *muxer;
>      int use_rename;
> +    int strftime_start_realtime;
>  } VideoMuxData;
>
>  static int write_header(AVFormatContext *s)
> @@ -105,6 +107,37 @@ static int write_packet(AVFormatContext *s, AVPacket
> *pkt)
>                  av_log(s, AV_LOG_ERROR, "Cannot write filename by pts of
> the frames.");
>                  return AVERROR(EINVAL);
>              }
> +        } else if (img->strftime_start_realtime) {
> +            int64_t start_realtime = s->start_time_realtime;
> +            int64_t timestamp = 0;
> +            struct tm *tm;
> +            time_t sec = 0;
> +
> +            if (start_realtime == 0 || start_realtime == AV_NOPTS_VALUE) {
> +                // the value is not set by either user or encoder, try
> use creation_time
> +                if (ff_parse_creation_time_metadata(s, &start_realtime,
> 0) != 0)
> +                    av_log(s, AV_LOG_INFO, "Use creation_time as
> start_realtime.\n");
> +
> +                if (start_realtime == 0 || start_realtime ==
> AV_NOPTS_VALUE) {
> +                    av_log(s, AV_LOG_WARNING, "Could not get
> start_time_realtime, set value to now.\n");
> +                    timestamp = av_gettime();
> +                    s->start_time_realtime = timestamp;
> +                } else {
> +                    s->start_time_realtime = start_realtime;
> +                }
> +            }
> +
> +            if (!timestamp) {
> +                int64_t offset = av_rescale_q(pkt->pts,
> s->streams[0]->time_base, AV_TIME_BASE_Q);
> +                timestamp = s->start_time_realtime + offset;
> +            }
> +
> +            sec = timestamp / AV_TIME_BASE;
> +            tm = gmtime(&sec);
> +            if (!strftime(filename, sizeof(filename), img->path, tm)) {
> +                av_log(s, AV_LOG_ERROR, "Could not get frame filename
> with strftime\n");
> +                return AVERROR(EINVAL);
> +            }
>          } else if (av_get_frame_filename2(filename, sizeof(filename),
> img->path,
>                                            img->img_number,
>
>  AV_FRAME_FILENAME_FLAGS_MULTIPLE) < 0 &&
> @@ -215,6 +248,7 @@ static const AVOption muxoptions[] = {
>      { "strftime",     "use strftime for filename", OFFSET(use_strftime),
> AV_OPT_TYPE_BOOL, { .i64 = 0 }, 0, 1, ENC },
>      { "frame_pts",    "use current frame pts for filename",
> OFFSET(frame_pts),  AV_OPT_TYPE_BOOL, { .i64 = 0 }, 0, 1, ENC },
>      { "atomic_writing", "write files atomically (using temporary files
> and renames)", OFFSET(use_rename), AV_OPT_TYPE_BOOL, { .i64 = 0 }, 0, 1,
> ENC },
> +    { "strftime_start_realtime", "use strftime for filename and timestamp
> calculated from start_time_realtime", OFFSET(strftime_start_realtime),
> AV_OPT_TYPE_BOOL, { .i64 = 0 }, 0, 1, ENC },
>      { NULL },
>  };
>
> --
> 2.17.1


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