[FFmpeg-devel] [PATCH] lavf/segment: add reference_stream option
Paul B Mahol
onemda at gmail.com
Wed Dec 26 20:39:50 CET 2012
On 12/22/12, Stefano Sabatini <stefasab at gmail.com> wrote:
> ---
> doc/muxers.texi | 11 ++++++++-
> libavformat/segment.c | 64
> +++++++++++++++++++++++++++++++++++++++----------
> 2 files changed, 61 insertions(+), 14 deletions(-)
>
> diff --git a/doc/muxers.texi b/doc/muxers.texi
> index 25cf565..e8c4a52 100644
> --- a/doc/muxers.texi
> +++ b/doc/muxers.texi
> @@ -493,7 +493,9 @@ streaming output formats, i.e. which do not require
> global headers,
> and is recommended for outputting e.g. to MPEG transport stream segments.
> @code{ssegment} is a shorter alias for @code{stream_segment}.
>
> -Every segment starts with a video keyframe, if a video stream is present.
> +Every segment starts with a keyframe of the selected reference stream,
> +which is set through the @option{reference_stream} option.
> +
> Note that if you want accurate splitting for a video file, you need to
> make the input key frames correspond to the exact splitting times
> expected by the segmenter, or the segment muxer will start the new
> @@ -509,6 +511,13 @@ the option @var{segment_list}. The list type is
> specified by the
> The segment muxer supports the following options:
>
> @table @option
> + at item reference_stream @var{specifier}
> +Set the reference stream, as specified by the string @var{specifier}.
> +If @var{specifier} is set to @code{auto}, the reference is choosen
> +automatically. Otherwise it is a stream specifier (see the ``Stream
> +specifiers'' chapter in the ffmpeg manual). The default value is
> +``auto''.
> +
> @item segment_format @var{format}
> Override the inner container format, by default it is guessed by the
> filename
> extension.
> diff --git a/libavformat/segment.c b/libavformat/segment.c
> index dc9b9c8..b46de10 100644
> --- a/libavformat/segment.c
> +++ b/libavformat/segment.c
> @@ -74,7 +74,9 @@ typedef struct {
> int write_header_trailer; /**< Set by a private option. */
>
> int reset_timestamps; ///< reset timestamps at the begin of each
> segment
> - int has_video;
> + char *reference_stream_specifier; ///< reference stream specifier
> + int reference_stream_index;
> +
> double start_time, end_time;
> int64_t start_pts, start_dts;
> int is_first_pkt; ///< tells if it is the first packet in the
> segment
> @@ -398,14 +400,51 @@ static int seg_write_header(AVFormatContext *s)
> if (seg->list_type == LIST_TYPE_EXT)
> av_log(s, AV_LOG_WARNING, "'ext' list type option is deprecated in
> favor of 'csv'\n");
>
> - for (i = 0; i < s->nb_streams; i++)
> - seg->has_video +=
> - (s->streams[i]->codec->codec_type == AVMEDIA_TYPE_VIDEO);
> + seg->reference_stream_index = -1;
> + if (!strcmp(seg->reference_stream_specifier, "auto")) {
> + int first_id[AVMEDIA_TYPE_NB];
> +
> + for (i = 0; i < AVMEDIA_TYPE_NB; i++)
> + first_id[i] = -1;
> +
> + for (i = 0; i < s->nb_streams; i++) {
> + enum AVMediaType type_priority_list[] = {
static const?
Move somewhere else?
Is this actually used?
> + AVMEDIA_TYPE_VIDEO,
> + AVMEDIA_TYPE_AUDIO,
> + AVMEDIA_TYPE_SUBTITLE,
> + AVMEDIA_TYPE_DATA,
> + AVMEDIA_TYPE_ATTACHMENT
> + };
> + enum AVMediaType type = s->streams[i]->codec->codec_type;
> + first_id[type] = FFMAX(first_id[type], i);
> +
> + for (i = 0; i < FF_ARRAY_ELEMS(type_priority_list); i++)
> + if ((seg->reference_stream_index = first_id[i]) >= 0)
> + break;
> + }
> + } else {
> + for (i = 0; i < s->nb_streams; i++) {
> + ret = avformat_match_stream_specifier(s, s->streams[i],
> +
> seg->reference_stream_specifier);
> + if (ret < 0)
> + goto fail;
> + if (ret > 0) {
> + seg->reference_stream_index = i;
> + break;
> + }
> + }
> + }
> +
> + if (seg->reference_stream_index < 0) {
> + av_log(s, AV_LOG_ERROR, "Could not select stream matching
> identifier '%s'\n",
> + seg->reference_stream_specifier);
> + ret = AVERROR(EINVAL);
> + goto fail;
> + }
>
> - if (seg->has_video > 1)
> - av_log(s, AV_LOG_WARNING,
> - "More than a single video stream present, "
> - "expect issues decoding it.\n");
> + av_log(s, AV_LOG_VERBOSE, "Selected stream id:%d type:%s\n",
> + seg->reference_stream_index,
> +
> av_get_media_type_string(s->streams[seg->reference_stream_index]->codec->codec_type));
>
> seg->oformat = av_guess_format(seg->format, s->filename, NULL);
>
> @@ -478,12 +517,10 @@ static int seg_write_packet(AVFormatContext *s,
> AVPacket *pkt)
> end_pts = seg->time * seg->segment_count;
> }
>
> - /* if the segment has video, start a new segment *only* with a key
> video frame */
> - if ((st->codec->codec_type == AVMEDIA_TYPE_VIDEO || !seg->has_video)
> &&
> + if (pkt->stream_index == seg->reference_stream_index &&
> + pkt->flags & AV_PKT_FLAG_KEY &&
> pkt->pts != AV_NOPTS_VALUE &&
> - av_compare_ts(pkt->pts, st->time_base,
> - end_pts-seg->time_delta, AV_TIME_BASE_Q) >= 0 &&
> - pkt->flags & AV_PKT_FLAG_KEY) {
> + av_compare_ts(pkt->pts, st->time_base, end_pts-seg->time_delta,
> AV_TIME_BASE_Q) >= 0) {
> ret = segment_end(s, seg->individual_header_trailer);
>
> if (!ret)
> @@ -565,6 +602,7 @@ fail:
> #define OFFSET(x) offsetof(SegmentContext, x)
> #define E AV_OPT_FLAG_ENCODING_PARAM
> static const AVOption options[] = {
> + { "reference_stream", "set reference stream",
> OFFSET(reference_stream_specifier), AV_OPT_TYPE_STRING, {.str = "auto"},
> CHAR_MIN, CHAR_MAX, E },
> { "segment_format", "set container format used for the segments",
> OFFSET(format), AV_OPT_TYPE_STRING, {.str = NULL}, 0, 0, E },
> { "segment_list", "set the segment list filename",
> OFFSET(list), AV_OPT_TYPE_STRING, {.str = NULL}, 0, 0, E },
>
> --
> 1.7.9.5
>
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