[FFmpeg-devel] [PATCH] Added queueing for OutputStreams to sidestep DVB subtitle encoding bug.

[Wim Vander Schelden]

Seems like something went wrong when pasting the patch into my email
client, I've attached it to this mail instead.


On Fri, Nov 15, 2013 at 4:50 PM, Wim Vander Schelden <wim at fixnum.org> wrote:

>
> Hi,
>
> I've got a possible solution for http://trac.ffmpeg.org/ticket/2024. It's
> not the prettiest or most elegant solution, but it "works for my samples
> "™. I'm open to feedback on how to improve this, I'd love to get this fix
> merged.
>
> Kind regards,
>
> Wim Vander Schelden
> http://fixnum.org
>
> From: Wim Vander Schelden <wim at fixnum.org>
> Date: Fri, 15 Nov 2013 16:40:32 +0100
> Subject: [PATCH] Added queueing for OutputStreams to sidestep DVB subtitle
>  encoding bug.
>
>
> Signed-off-by: Wim Vander Schelden <wim at fixnum.org>
> ---
>  ffmpeg.c | 54 +++++++++++++++++++++++++++++++++++++++++++++++++++++-
>  ffmpeg.h |  9 +++++++++
>  2 files changed, 62 insertions(+), 1 deletion(-)
>
> diff --git a/ffmpeg.c b/ffmpeg.c
> index 2a88535..2177784 100644
> --- a/ffmpeg.c
> +++ b/ffmpeg.c
> @@ -543,6 +543,51 @@ static void update_benchmark(const char *fmt, ...)
>      }
>  }
>
> +#define STAMP(pkt) ( ((pkt)->dts == AV_NOPTS_VALUE) ? (pkt)->pts :
> (pkt)->dts)
> +
> +static void write_frame(AVFormatContext *s, AVPacket *pkt, OutputStream
> *ost);
> +static void queue_frame(AVFormatContext *s, AVPacket *pkt, OutputStream
> *ost)
> +{
> +    PacketQueue *last = ost->queue, *new;
> +    new = av_mallocz(sizeof(PacketQueue));
> +    new->s   = s;
> +    new->pkt = av_memdup(pkt, sizeof(AVPacket));
> +    new->ost = ost;
> +
> +    if(STAMP(pkt) == AV_NOPTS_VALUE) {
> +       write_frame(s, pkt, ost);
> +       return;
> +    }
> +
> +    if(!last) {
> +       ost->queue = new;
> +       return;
> +    }
> +
> +    while(last && last->next && STAMP(last->next->pkt) < STAMP(pkt)) {
> +       last = last->next;
> +    }
> +
> +    new->next  = last->next;
> +    last->next = new;
> +}
> +
> +static void flush_queue(OutputStream *ost, int64_t ts)
> +{
> +    PacketQueue *last;
> +
> +    if(ts == AV_NOPTS_VALUE)
> +       return;
> +
> +    while(ost->queue && STAMP(ost->queue->pkt) <= ts) {
> +       last = ost->queue;
> +       ost->queue = ost->queue->next;
> +       write_frame(last->s, last->pkt, last->ost);
> +       av_free(last->pkt);
> +       av_free(last);
> +    }
> +}
> +
>  static void write_frame(AVFormatContext *s, AVPacket *pkt, OutputStream
> *ost)
>  {
>      AVBitStreamFilterContext *bsfc = ost->bitstream_filters;
> @@ -604,6 +649,8 @@ static void write_frame(AVFormatContext *s, AVPacket
> *pkt, OutputStream *ost)
>          bsfc = bsfc->next;
>      }
>
> +    flush_queue(ost, STAMP(pkt));
> +
>      if (!(s->oformat->flags & AVFMT_NOTIMESTAMPS) &&
>          (avctx->codec_type == AVMEDIA_TYPE_AUDIO || avctx->codec_type ==
> AVMEDIA_TYPE_VIDEO) &&
>          pkt->dts != AV_NOPTS_VALUE &&
> @@ -651,6 +698,8 @@ static void close_output_stream(OutputStream *ost)
>  {
>      OutputFile *of = output_files[ost->file_index];
>
> +    flush_queue(ost, INT64_MAX);
> +
>      ost->finished = 1;
>      if (of->shortest) {
>          int64_t end = av_rescale_q(ost->sync_opts - ost->first_pts,
> ost->st->codec->time_base, AV_TIME_BASE_Q);
> @@ -788,7 +837,10 @@ static void do_subtitle_out(AVFormatContext *s,
>                  pkt.pts += 90 * sub->end_display_time;
>          }
>          subtitle_size += pkt.size;
> -        write_frame(s, &pkt, ost);
> +       if(i == 0)
> +           write_frame(s, &pkt, ost);
> +       else
> +           queue_frame(s, &pkt, ost);
>      }
>  }
>
> diff --git a/ffmpeg.h b/ffmpeg.h
> index 409525c..6968135 100644
> --- a/ffmpeg.h
> +++ b/ffmpeg.h
> @@ -312,6 +312,14 @@ enum forced_keyframes_const {
>
>  extern const char *const forced_keyframes_const_names[];
>
> +struct OutputStream;
> +typedef struct PacketQueue {
> +    AVFormatContext *s;
> +    AVPacket *pkt;
> +    struct OutputStream *ost;
> +    struct PacketQueue *next;
> +} PacketQueue;
> +
>  typedef struct OutputStream {
>      int file_index;          /* file index */
>      int index;               /* stream index in the output file */
> @@ -375,6 +383,7 @@ typedef struct OutputStream {
>      int keep_pix_fmt;
>
>      AVCodecParserContext *parser;
> +    PacketQueue *queue;
>  } OutputStream;
>
>  typedef struct OutputFile {
> --
> 1.8.1.4
>
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