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clamp intra matrix to 8bit for mjpeg (workaround for qscale>=25)

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Originally committed as revision 451 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Alex Beregszaszi 2002-05-07 17:55:02 +00:00
parent 723106b279
commit a69b930cd3
4 changed files with 9 additions and 2 deletions
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2
libavcodec/common.h
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@ -902,4 +902,6 @@ void *av_mallocz(int size);
/* math */
int ff_gcd(int a, int b);
#define CLAMP_TO_8BIT(d) ((d > 0xff) ? 0xff : (d < 0) ? 0 : d)
#endif

3
libavcodec/mjpeg.c
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@ -388,6 +388,8 @@ void mjpeg_picture_header(MpegEncContext *s)
{
put_marker(&s->pb, SOI);
if (!s->mjpeg_data_only_frames)
{
jpeg_put_comments(s);
if (s->mjpeg_write_tables) jpeg_table_header(s);
@ -425,6 +427,7 @@ void mjpeg_picture_header(MpegEncContext *s)
#else
put_bits(&s->pb, 8, 0); /* select matrix */
#endif
}
/* scan header */
put_marker(&s->pb, SOS);

5
libavcodec/mpegvideo.c
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@ -427,10 +427,11 @@ int MPV_encode_init(AVCodecContext *avctx)
s->out_format = FMT_MJPEG;
s->intra_only = 1; /* force intra only for jpeg */
s->mjpeg_write_tables = 1; /* write all tables */
s->mjpeg_data_only_frames = 0; /* write all the needed headers */
s->mjpeg_vsample[0] = 2; /* set up default sampling factors */
s->mjpeg_vsample[1] = 1; /* the only currently supported values */
s->mjpeg_vsample[2] = 1;
s->mjpeg_hsample[0] = 2;
s->mjpeg_hsample[0] = 2;
s->mjpeg_hsample[1] = 1;
s->mjpeg_hsample[2] = 1;
if (mjpeg_init(s) < 0)
@ -1658,7 +1659,7 @@ static void encode_picture(MpegEncContext *s, int picture_number)
/* for mjpeg, we do include qscale in the matrix */
s->intra_matrix[0] = default_intra_matrix[0];
for(i=1;i<64;i++)
s->intra_matrix[i] = (default_intra_matrix[i] * s->qscale) >> 3;
s->intra_matrix[i] = CLAMP_TO_8BIT((default_intra_matrix[i] * s->qscale) >> 3);
convert_matrix(s->q_intra_matrix, s->q_intra_matrix16,
s->q_intra_matrix16_bias, s->intra_matrix, s->intra_quant_bias);
}

1
libavcodec/mpegvideo.h
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@ -332,6 +332,7 @@ typedef struct MpegEncContext {
int mjpeg_hsample[3]; /* horizontal sampling factors, default = {2, 1, 1} */
int mjpeg_write_tables; /* do we want to have quantisation- and
huffmantables in the jpeg file ? */
int mjpeg_data_only_frames; /* frames only with SOI, SOS and EOI markers */
/* MSMPEG4 specific */
int mv_table_index;