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change the way the ImageDescription is passed to the decoder

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Originally committed as revision 1846 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Mike Melanson 2003-05-10 04:30:29 +00:00
parent 8b82a95675
commit 89a79364ed
1 changed files with 19 additions and 13 deletions
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32
libavcodec/svq3.c
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@ -18,17 +18,23 @@
*
* How to use this decoder:
* SVQ3 data is transported within Apple Quicktime files. Quicktime files
* have stsd atoms to describe media trak properties. Sometimes the stsd
* atom contains information that the decoder must know in order to function
* properly. Such is the case with SVQ3. In order to get the best use out
* of this decoder, the calling app must make the video stsd atom available
* have stsd atoms to describe media trak properties. A stsd atom for a
* video trak contains 1 or more ImageDescription atoms. These atoms begin
* with the 4-byte length of the atom followed by the codec fourcc. Some
* decoders need information in this atom to operate correctly. Such
* is the case with SVQ3. In order to get the best use out of this decoder,
* the calling app must make the SVQ3 ImageDescription atom available
* via the AVCodecContext's extradata[_size] field:
*
* AVCodecContext.extradata = pointer to stsd, first characters are expected
* to be 's', 't', 's', and 'd', NOT the atom length
* AVCodecContext.extradata_size = size of stsd atom memory buffer (which
* will be the same as the stsd atom size field from the QT file, minus 4
* bytes since the length is missing.
* AVCodecContext.extradata = pointer to ImageDescription, first characters
* are expected to be 'S', 'V', 'Q', and '3', NOT the 4-byte atom length
* AVCodecContext.extradata_size = size of ImageDescription atom memory
* buffer (which will be the same as the ImageDescription atom size field
* from the QT file, minus 4 bytes since the length is missing)
*
* You will know you have these parameters passed correctly when the decoder
* correctly decodes this file:
* ftp://ftp.mplayerhq.hu/MPlayer/samples/V-codecs/SVQ3/Vertical400kbit.sorenson3.mov
*
*/
@ -667,12 +673,12 @@ static int svq3_decode_frame (AVCodecContext *avctx,
alloc_tables (h);
}
if (avctx->extradata && avctx->extradata_size >= 115
&& !memcmp (avctx->extradata, "stsd", 4)) {
if (avctx->extradata && avctx->extradata_size >= 0x63
&& !memcmp (avctx->extradata, "SVQ3", 4)) {
uint8_t *stsd = (uint8_t *) avctx->extradata + 114;
uint8_t *stsd = (uint8_t *) avctx->extradata + 0x62;
if ((*stsd >> 5) != 7 || avctx->extradata_size >= 118) {
if ((*stsd >> 5) != 7 || avctx->extradata_size >= 0x66) {
if ((*stsd >> 5) == 7) {
stsd += 3; /* skip width, height (12 bits each) */