| Message ID | 20180610230837.28726-1-cus@passwd.hu |
|---|---|
| State | Accepted |
| Commit | b1e0e216462a989a39e7b413aef6d32f8cedc154 |
| Headers | show |
On Mon, 11 Jun 2018, Marton Balint wrote: > This works around a libzvbi bug (a corner case in the teletext spec): > > https://sourceforge.net/p/zapping/bugs/203/ > https://sourceforge.net/p/zapping/patches/20/ > > Fixes samples/ffmpeg-bugs/trac/ticket2086/RBT_20100801_1835.ts. > > Signed-off-by: Marton Balint <cus@passwd.hu> > --- > libavcodec/libzvbi-teletextdec.c | 15 +++++++++++++++ > 1 file changed, 15 insertions(+) > > diff --git a/libavcodec/libzvbi-teletextdec.c b/libavcodec/libzvbi-teletextdec.c > index ccded23e7c..809547545b 100644 > --- a/libavcodec/libzvbi-teletextdec.c > +++ b/libavcodec/libzvbi-teletextdec.c > @@ -74,6 +74,8 @@ typedef struct TeletextContext > > int readorder; > uint8_t subtitle_map[2048]; > + int last_pgno; > + int last_p5; > } TeletextContext; > > static int chop_spaces_utf8(const unsigned char* t, int len) > @@ -372,6 +374,17 @@ static int slice_to_vbi_lines(TeletextContext *ctx, uint8_t* buf, int size) > int pgno = ((pmag & 7) << 8) + page; > // Check for disabled NEWSFLASH flag and enabled SUBTITLE and SUPRESS_HEADER flags > ctx->subtitle_map[pgno] = (!(flags1 & 0x40) && flags1 & 0x80 && flags2 & 0x01); > + // Propagate ERASE_PAGE flag for repeated page headers to work around a libzvbi bug > + if (ctx->subtitle_map[pgno] && pgno == ctx->last_pgno) { > + int last_byte9 = vbi_unham8(ctx->last_p5); > + if (last_byte9 >= 0 && last_byte9 & 0x8) { > + int byte9 = vbi_unham8(p[5]); > + if (byte9 >= 0) > + p[5] = vbi_ham8(byte9 | 0x8); > + } > + } > + ctx->last_pgno = pgno; > + ctx->last_p5 = p[5]; > } > } > lines++; > @@ -494,6 +507,7 @@ static int teletext_init_decoder(AVCodecContext *avctx) > > ctx->vbi = NULL; > ctx->pts = AV_NOPTS_VALUE; > + ctx->last_pgno = -1; > > if (ctx->opacity == -1) > ctx->opacity = ctx->transparent_bg ? 0 : 255; > @@ -514,6 +528,7 @@ static int teletext_close_decoder(AVCodecContext *avctx) > vbi_decoder_delete(ctx->vbi); > ctx->vbi = NULL; > ctx->pts = AV_NOPTS_VALUE; > + ctx->last_pgno = -1; > memset(ctx->subtitle_map, 0, sizeof(ctx->subtitle_map)); > if (!(avctx->flags2 & AV_CODEC_FLAG2_RO_FLUSH_NOOP)) > ctx->readorder = 0; > -- Pushed. Regards, Marton
diff --git a/libavcodec/libzvbi-teletextdec.c b/libavcodec/libzvbi-teletextdec.c index ccded23e7c..809547545b 100644 --- a/libavcodec/libzvbi-teletextdec.c +++ b/libavcodec/libzvbi-teletextdec.c @@ -74,6 +74,8 @@ typedef struct TeletextContext int readorder; uint8_t subtitle_map[2048]; + int last_pgno; + int last_p5; } TeletextContext; static int chop_spaces_utf8(const unsigned char* t, int len) @@ -372,6 +374,17 @@ static int slice_to_vbi_lines(TeletextContext *ctx, uint8_t* buf, int size) int pgno = ((pmag & 7) << 8) + page; // Check for disabled NEWSFLASH flag and enabled SUBTITLE and SUPRESS_HEADER flags ctx->subtitle_map[pgno] = (!(flags1 & 0x40) && flags1 & 0x80 && flags2 & 0x01); + // Propagate ERASE_PAGE flag for repeated page headers to work around a libzvbi bug + if (ctx->subtitle_map[pgno] && pgno == ctx->last_pgno) { + int last_byte9 = vbi_unham8(ctx->last_p5); + if (last_byte9 >= 0 && last_byte9 & 0x8) { + int byte9 = vbi_unham8(p[5]); + if (byte9 >= 0) + p[5] = vbi_ham8(byte9 | 0x8); + } + } + ctx->last_pgno = pgno; + ctx->last_p5 = p[5]; } } lines++; @@ -494,6 +507,7 @@ static int teletext_init_decoder(AVCodecContext *avctx) ctx->vbi = NULL; ctx->pts = AV_NOPTS_VALUE; + ctx->last_pgno = -1; if (ctx->opacity == -1) ctx->opacity = ctx->transparent_bg ? 0 : 255; @@ -514,6 +528,7 @@ static int teletext_close_decoder(AVCodecContext *avctx) vbi_decoder_delete(ctx->vbi); ctx->vbi = NULL; ctx->pts = AV_NOPTS_VALUE; + ctx->last_pgno = -1; memset(ctx->subtitle_map, 0, sizeof(ctx->subtitle_map)); if (!(avctx->flags2 & AV_CODEC_FLAG2_RO_FLUSH_NOOP)) ctx->readorder = 0;
This works around a libzvbi bug (a corner case in the teletext spec): https://sourceforge.net/p/zapping/bugs/203/ https://sourceforge.net/p/zapping/patches/20/ Fixes samples/ffmpeg-bugs/trac/ticket2086/RBT_20100801_1835.ts. Signed-off-by: Marton Balint <cus@passwd.hu> --- libavcodec/libzvbi-teletextdec.c | 15 +++++++++++++++ 1 file changed, 15 insertions(+)