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ffmpeg: don't pass pointer as hexadecimal string

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Casting a pointer to some sort of integer and formatting it into a
string isn't valid.  A pointer derived from this hex string won't work
reliably.  Since ffmpeg doesn't provide a nice API for passing our
pointer, we have to think of a different hack: ffmpeg passes the exact
URL pointer to mpdurl_open(), and we can make this string part of a
struct.  This reduces the problem to casting the string back to the
struct.

This is still a workaround, but this is "sort of portable", unless the
ffmpeg people start messing with the URL pointer (which would be valid
according to the API definition).
This commit is contained in:
Max Kellermann 2008-10-21 18:12:56 +02:00
parent e4df17f611
commit a7888c4998
1 changed files with 27 additions and 20 deletions
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47
src/inputPlugins/ffmpeg_plugin.c
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@ -50,26 +50,34 @@ typedef struct {
} BasePtrs; } BasePtrs;
typedef struct { typedef struct {
/** hack - see url_to_base() */
char url[8];
struct decoder *decoder; struct decoder *decoder;
InputStream *input; InputStream *input;
} FopsHelper; } FopsHelper;
static int mpdurl_open(URLContext *h, const char *filename, int flags) /**
* Convert a faked mpd:// URL to a FopsHelper structure. This is a
* hack because ffmpeg does not provide a nice API for passing a
* user-defined pointer to mpdurl_open().
*/
static FopsHelper *url_to_base(const char *url)
{ {
uint32_t ptr; union {
FopsHelper *base; const char *in;
if (strlen(filename) == (8+8)) { FopsHelper *out;
errno = 0; } u = { .in = url };
ptr = (uint32_t) strtoll(filename + 6, NULL, 16); return u.out;
if (errno == 0 && ptr != 0) { }
base = (FopsHelper *) ptr;
h->priv_data = base; static int mpdurl_open(URLContext *h, const char *filename,
h->is_streamed = (base->input->seekable ? 0 : 1); mpd_unused int flags)
return 0; {
} FopsHelper *base = url_to_base(filename);
} h->priv_data = base;
FATAL("Invalid format %s:%d\n", filename, flags); h->is_streamed = (base->input->seekable ? 0 : 1);
return -1; return 0;
} }
static int mpdurl_read(URLContext *h, unsigned char *buf, int size) static int mpdurl_read(URLContext *h, unsigned char *buf, int size)
@ -137,8 +145,9 @@ static int ffmpeg_helper(InputStream *input, int (*callback)(BasePtrs *ptrs),
AVCodec *aCodec; AVCodec *aCodec;
int ret, audioStream; int ret, audioStream;
unsigned i; unsigned i;
FopsHelper fopshelp; FopsHelper fopshelp = {
char url[24]; .url = "mpd://X", /* only the mpd:// prefix matters */
};
fopshelp.input = input; fopshelp.input = input;
if (ptrs && ptrs->decoder) { if (ptrs && ptrs->decoder) {
@ -148,9 +157,7 @@ static int ffmpeg_helper(InputStream *input, int (*callback)(BasePtrs *ptrs),
} }
//ffmpeg works with ours "fileops" helper //ffmpeg works with ours "fileops" helper
sprintf(url, "mpd://0x%8x", (unsigned int) &fopshelp); if (av_open_input_file(&pFormatCtx, fopshelp.url, NULL, 0, NULL)!=0) {
if (av_open_input_file(&pFormatCtx, url, NULL, 0, NULL)!=0) {
ERROR("Open failed!\n"); ERROR("Open failed!\n");
return -1; return -1;
} }