[FFmpeg-devel] [PATCH] MTH demuxer (Gamecube format)

[Michael Niedermayer]

On Tue, Feb 03, 2009 at 10:02:01PM -0500, Michael Montanye wrote:
> Michael Niedermayer wrote:
>>> Without it, decoding terminates on the first frame with an empty frame.
>>>     
>> [...]
>>   
>>> +    mth->first_frame     = get_be32(pb);
>>>     
>>
>> you need to seek to this at the end of reading the header
>>
>>   
> Ah.  Fixed.
>>> +static int mth_read_packet(AVFormatContext *s, AVPacket *pkt)
>>> +{
>>> +    MthDemuxContext *mth = s->priv_data;
>>> +    ByteIOContext *pb = s->pb;
>>> +    int size;
>>> +    int ret;
>>> +
>>> +    url_fseek(pb, mth->next_frame, SEEK_SET);
>>> +
>>> +    size = mth->next_framesz;
>>> +
>>> +    /* Locate the next frame and read out its size.  */
>>> +    mth->next_frame   += mth->next_framesz;
>>> +    mth->next_framesz  = get_be32(pb);
>>> +
>>> +    ret = av_get_packet(pb, pkt, size);
>>>     
>>
>> this looks odd
>> if the value stored is the difference between frames it cant at the
>> same time be the size of the codec frame, (theres should be a 4 byte
>> difference)
> You're right; having the seek in mth_read_packet was hiding that four-byte 
> overreach.  Fixed.
>
>>> +    if (ret != size) {
>>> +		if (ret >= 0) {
>>> +        	av_free_packet(pkt);
>>> +		}
>>>     
>>
>> tabs
>>
>>   
> I thought I had changed that in this editor.  Fixed, new patch attached.

[...]

> +#include "libavutil/intreadwrite.h"

is this needed?


> +#include "avformat.h"
> +
> +typedef struct MthDemuxContext {

> +    int              first_frame;
> +    int              first_framesz;

unused


> +    int              next_frame;

can be a local var

[...]
> +static int mth_read_header(AVFormatContext *s,
> +                           AVFormatParameters *ap)
> +{
> +    MthDemuxContext *mth = s->priv_data;
> +    AVStream        *st;
> +    ByteIOContext   *pb  = s->pb;
> +
> +    int             width;
> +    int             height;
> +    int             fps;
> +
> +    /* Read the file header.  */
> +                           get_be32(pb); /* Skip Magic.  */
> +                           get_be32(pb); /* Unknown value */
> +                           get_be32(pb); /* Unknown value */
> +                           get_be32(pb); /* Unknown value */
> +
> +    width                = get_be32(pb);
> +    height               = get_be32(pb);
> +    fps                  = get_be32(pb);
> +

> +                           get_be32(pb); /* Framecount, not needed */

maybe AVStream.duration could be set with that

[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Let us carefully observe those good qualities wherein our enemies excel us
and endeavor to excel them, by avoiding what is faulty, and imitating what
is excellent in them. -- Plutarch
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