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fix mjpeg decoding with broken huffman table headers

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Originally committed as revision 9111 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Oded Shimon 2007-05-23 18:41:34 +00:00
parent 82e605410a
commit 8d641aedb9
1 changed files with 16 additions and 10 deletions
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26
libavcodec/mjpegdec.c
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@ -62,6 +62,17 @@ static int build_vlc(VLC *vlc, const uint8_t *bits_table, const uint8_t *val_tab
return init_vlc(vlc, 9, nb_codes, huff_size, 1, 1, huff_code, 2, 2, use_static);
}
static void build_basic_mjpeg_vlc(MJpegDecodeContext * s) {
build_vlc(&s->vlcs[0][0], ff_mjpeg_bits_dc_luminance,
ff_mjpeg_val_dc_luminance, 12, 0, 0);
build_vlc(&s->vlcs[0][1], ff_mjpeg_bits_dc_chrominance,
ff_mjpeg_val_dc_chrominance, 12, 0, 0);
build_vlc(&s->vlcs[1][0], ff_mjpeg_bits_ac_luminance,
ff_mjpeg_val_ac_luminance, 251, 0, 1);
build_vlc(&s->vlcs[1][1], ff_mjpeg_bits_ac_chrominance,
ff_mjpeg_val_ac_chrominance, 251, 0, 1);
}
int ff_mjpeg_decode_init(AVCodecContext *avctx)
{
MJpegDecodeContext *s = avctx->priv_data;
@ -75,21 +86,16 @@ int ff_mjpeg_decode_init(AVCodecContext *avctx)
s->first_picture = 1;
s->org_height = avctx->coded_height;
build_vlc(&s->vlcs[0][0], ff_mjpeg_bits_dc_luminance,
ff_mjpeg_val_dc_luminance, 12, 0, 0);
build_vlc(&s->vlcs[0][1], ff_mjpeg_bits_dc_chrominance,
ff_mjpeg_val_dc_chrominance, 12, 0, 0);
build_vlc(&s->vlcs[1][0], ff_mjpeg_bits_ac_luminance,
ff_mjpeg_val_ac_luminance, 251, 0, 1);
build_vlc(&s->vlcs[1][1], ff_mjpeg_bits_ac_chrominance,
ff_mjpeg_val_ac_chrominance, 251, 0, 1);
build_basic_mjpeg_vlc(s);
if (avctx->flags & CODEC_FLAG_EXTERN_HUFF)
{
av_log(avctx, AV_LOG_INFO, "mjpeg: using external huffman table\n");
init_get_bits(&s->gb, avctx->extradata, avctx->extradata_size*8);
ff_mjpeg_decode_dht(s);
/* should check for error - but dunno */
if (ff_mjpeg_decode_dht(s)) {
av_log(avctx, AV_LOG_ERROR, "mjpeg: error using external huffman table, switching back to internal\n");
build_basic_mjpeg_vlc(s);
}
}
if (avctx->extradata_size > 9 &&
AV_RL32(avctx->extradata + 4) == MKTAG('f','i','e','l')) {