[FFmpeg-devel] [PATCH] Fix MJPEG decoding with broken AVI header
Oded Shimon
ods15
Wed May 23 18:09:12 CEST 2007
The following patch fixes decoding of this file:
ftp.mplayerhq.hu/incoming/picnotinterlace.avi
File was created using virtualdub and Pegasus MJPEG 3.0 (from what I
know..)
Better name for "build_basic_mjpeg_vlc" and better error message
suggestions welcome..
(Alternative implementation for this fix is to remove the EXTERNAL_HUFF
flag and recursively call ff_mjpeg_decode_init)
Can I commit?
- ods15
-------------- next part --------------
Index: libavcodec/mjpegdec.c
===================================================================
--- libavcodec/mjpegdec.c (revision 9108)
+++ libavcodec/mjpegdec.c (working copy)
@@ -62,6 +62,17 @@
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 @@
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')) {
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