[FFmpeg-devel] [PATCH] h264: revert 1189af429211ac650aac730368a6cf5b23756605.

[Ronald S. Bultje]

Hi,

On Mon, Mar 27, 2017 at 9:49 AM, wm4 <nfxjfg at googlemail.com> wrote:

> On Mon, 27 Mar 2017 09:39:32 -0400
> "Ronald S. Bultje" <rsbultje at gmail.com> wrote:
>
> > The patch introduces race conditions.
> > ---
> >  libavcodec/h264_slice.c |  3 ---
> >  libavcodec/h264dec.c    | 20 --------------------
> >  libavcodec/h264dec.h    |  8 --------
> >  3 files changed, 31 deletions(-)
> >
> > diff --git a/libavcodec/h264_slice.c b/libavcodec/h264_slice.c
> > index a703853..fa1e9ae 100644
> > --- a/libavcodec/h264_slice.c
> > +++ b/libavcodec/h264_slice.c
> > @@ -383,9 +383,6 @@ int ff_h264_update_thread_context(AVCodecContext
> *dst,
> >      h->picture_structure    = h1->picture_structure;
> >      h->mb_aff_frame         = h1->mb_aff_frame;
> >      h->droppable            = h1->droppable;
> > -    h->backup_width         = h1->backup_width;
> > -    h->backup_height        = h1->backup_height;
> > -    h->backup_pix_fmt       = h1->backup_pix_fmt;
> >
> >      for (i = 0; i < H264_MAX_PICTURE_COUNT; i++) {
> >          ff_h264_unref_picture(h, &h->DPB[i]);
> > diff --git a/libavcodec/h264dec.c b/libavcodec/h264dec.c
> > index 9042169..be69e55 100644
> > --- a/libavcodec/h264dec.c
> > +++ b/libavcodec/h264dec.c
> > @@ -307,9 +307,6 @@ static int h264_init_context(AVCodecContext *avctx,
> H264Context *h)
> >      int i;
> >
> >      h->avctx                 = avctx;
> > -    h->backup_width          = -1;
> > -    h->backup_height         = -1;
> > -    h->backup_pix_fmt        = AV_PIX_FMT_NONE;
> >      h->cur_chroma_format_idc = -1;
> >
> >      h->picture_structure     = PICT_FRAME;
> > @@ -861,10 +858,6 @@ static int output_frame(H264Context *h, AVFrame
> *dst, H264Picture *srcp)
> >
> >      av_dict_set(&dst->metadata, "stereo_mode",
> ff_h264_sei_stereo_mode(&h->sei.frame_packing), 0);
> >
> > -    h->backup_width   = h->avctx->width;
> > -    h->backup_height  = h->avctx->height;
> > -    h->backup_pix_fmt = h->avctx->pix_fmt;
> > -
> >      h->avctx->width   = dst->width;
> >      h->avctx->height  = dst->height;
> >      h->avctx->pix_fmt = dst->format;
> > @@ -1003,19 +996,6 @@ static int h264_decode_frame(AVCodecContext
> *avctx, void *data,
> >      h->setup_finished = 0;
> >      h->nb_slice_ctx_queued = 0;
> >
> > -    if (h->backup_width != -1) {
> > -        avctx->width    = h->backup_width;
> > -        h->backup_width = -1;
> > -    }
> > -    if (h->backup_height != -1) {
> > -        avctx->height    = h->backup_height;
> > -        h->backup_height = -1;
> > -    }
> > -    if (h->backup_pix_fmt != AV_PIX_FMT_NONE) {
> > -        avctx->pix_fmt    = h->backup_pix_fmt;
> > -        h->backup_pix_fmt = AV_PIX_FMT_NONE;
> > -    }
> > -
> >      ff_h264_unref_picture(h, &h->last_pic_for_ec);
> >
> >      /* end of stream, output what is still in the buffers */
> > diff --git a/libavcodec/h264dec.h b/libavcodec/h264dec.h
> > index 5f868b7..e994f7e 100644
> > --- a/libavcodec/h264dec.h
> > +++ b/libavcodec/h264dec.h
> > @@ -363,14 +363,6 @@ typedef struct H264Context {
> >      int width, height;
> >      int chroma_x_shift, chroma_y_shift;
> >
> > -    /**
> > -     * Backup frame properties: needed, because they can be different
> > -     * between returned frame and last decoded frame.
> > -     **/
> > -    int backup_width;
> > -    int backup_height;
> > -    enum AVPixelFormat backup_pix_fmt;
> > -
> >      int droppable;
> >      int coded_picture_number;
> >
>
> Why was this even applied?
>

I've started wondering the same thing. Going back to the patch discussion
on the list, it looks like two developers (Michael and Hendrik) had
objections, but their comments were ignored. I did not see any comments
explicitly approving the patch.

Ronald