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libavformat/mtv: make clear we assume bpp is always 16

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All samples in the wild are RGB565/555 and we are already
acting on this assumption when pushing out the video frames,
so if we get anything != than 16 for bpp we just override
this value for doing any calculations making our approach
consistent.

Also avoid repeatedly shifting bpp.

Signed-off-by: Reynaldo H. Verdejo Pinochet <r.verdejo@sisa.samsung.com>
This commit is contained in:
Reynaldo H. Verdejo Pinochet 2014-01-23 16:18:57 -03:00
parent d467e7df1a
commit ba15aab4a4
1 changed files with 21 additions and 7 deletions
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28
libavformat/mtv.c
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@ -32,6 +32,7 @@
#define MTV_ASUBCHUNK_DATA_SIZE 500
#define MTV_HEADER_SIZE 512
#define MTV_AUDIO_PADDING_SIZE 12
#define MTV_IMAGE_DEFAULT_BPP 16
#define AUDIO_SAMPLING_RATE 44100
typedef struct MTVDemuxContext {
@ -75,8 +76,13 @@ static int mtv_probe(AVProbeData *p)
return 0;
}
if(p->buf[51] != 16)
return AVPROBE_SCORE_EXTENSION / 2; // But we are going to assume 16bpp anyway ..
/* Image bpp is not an absolutely required
* field as we latter claim it should be 16
* no matter what. All samples in the wild
* are RGB565/555.
*/
if(p->buf[51] != MTV_IMAGE_DEFAULT_BPP)
return AVPROBE_SCORE_EXTENSION / 2;
/* We had enough data to parse header values
* but we expect to be able to get 512 bytes
@ -102,22 +108,30 @@ static int mtv_read_header(AVFormatContext *s)
mtv->audio_identifier = avio_rl24(pb);
mtv->audio_br = avio_rl16(pb);
mtv->img_colorfmt = avio_rl24(pb);
mtv->img_bpp = avio_r8(pb);
mtv->img_bpp = avio_r8(pb)>>3;
mtv->img_width = avio_rl16(pb);
mtv->img_height = avio_rl16(pb);
mtv->img_segment_size = avio_rl16(pb);
/* Assume 16bpp even if claimed otherwise.
* We know its going to be RGBG565/555 anyway
*/
if (mtv->img_bpp != MTV_IMAGE_DEFAULT_BPP) {
av_log (s, AV_LOG_WARNING, "Header claims %dbpp (!= 16). Ignoring\n",
mtv->img_bpp);
mtv->img_bpp = MTV_IMAGE_DEFAULT_BPP;
}
/* Calculate width and height if missing from header */
if(mtv->img_bpp>>3){
if(!mtv->img_width && mtv->img_height)
mtv->img_width=mtv->img_segment_size / (mtv->img_bpp>>3)
mtv->img_width=mtv->img_segment_size / (mtv->img_bpp)
/ mtv->img_height;
if(!mtv->img_height && mtv->img_width)
mtv->img_height=mtv->img_segment_size / (mtv->img_bpp>>3)
mtv->img_height=mtv->img_segment_size / (mtv->img_bpp)
/ mtv->img_width;
}
if(!mtv->img_height || !mtv->img_width || !mtv->img_segment_size){
av_log(s, AV_LOG_ERROR, "width or height or segment_size is invalid and I cannot calculate them from other information\n");
return AVERROR(EINVAL);