[FFmpeg-devel] [HACK] Remove MAX_STREAMS usages

[Aurelien Jacobs]

On Wed, Aug 11, 2010 at 02:41:49PM -0700, Baptiste Coudurier wrote:
> Hi guys,
> 
> On 8/11/10 8:28 AM, Aurelien Jacobs wrote:
> >max_stream.diff
> >
> >
> >commit eb4a2bfc996713e70f60b556ed776cae3ab1cc5b
> >Author: Aurelien Jacobs<aurel at gnuage.org>
> >Date:   Tue Aug 10 00:21:06 2010 +0200
> >
> >     dynamically use nb_streams instead of static use of MAX_STREAMS
> >
> >diff --git a/libavformat/utils.c b/libavformat/utils.c
> >index 1aa965c..10e817d 100644
> >--- a/libavformat/utils.c
> >+++ b/libavformat/utils.c
> > [...]
> >@@ -2160,15 +2164,34 @@ int av_find_stream_info(AVFormatContext *ic)
> >      int i, count, ret, read_size, j;
> >      AVStream *st;
> >      AVPacket pkt1, *pkt;
> >-    int64_t last_dts[MAX_STREAMS];
> >-    int64_t duration_gcd[MAX_STREAMS]={0};
> >-    int duration_count[MAX_STREAMS]={0};
> >-    double (*duration_error)[MAX_STD_TIMEBASES];
> >+    int64_t *last_dts = NULL;
> >+    int64_t *duration_gcd = NULL;
> >+    int *duration_count = NULL;
> >+    double (*duration_error)[MAX_STD_TIMEBASES] = NULL;
> >      int64_t old_offset = url_ftell(ic->pb);
> >-    int64_t codec_info_duration[MAX_STREAMS]={0};
> >+    int64_t *codec_info_duration = NULL;
> >+    int nb_streams = 0;
> >+    void *tmp;
> >
> >-    duration_error = av_mallocz(MAX_STREAMS * sizeof(*duration_error));
> >-    if (!duration_error) return AVERROR(ENOMEM);
> >+#define GROW_BUFFER(buf, old_size, new_size)                           \
> >+    if (!(tmp = av_realloc(buf, new_size * sizeof(*buf)))) {           \
> >+        ret = AVERROR(ENOMEM);                                         \
> >+        goto err_out;                                                  \
> >+    }                                                                  \
> >+    buf = tmp;                                                         \
> >+    memset(buf+old_size, 0, (new_size-old_size) * sizeof(*buf));       \
> >+
> >+#define GROW_BUFFERS()                                                 \
> >+    if (ic->nb_streams>  nb_streams) {                                 \
> >+        GROW_BUFFER(last_dts,            nb_streams, ic->nb_streams);  \
> >+        GROW_BUFFER(duration_gcd,        nb_streams, ic->nb_streams);  \
> >+        GROW_BUFFER(duration_count,      nb_streams, ic->nb_streams);  \
> >+        GROW_BUFFER(duration_error,      nb_streams, ic->nb_streams);  \
> >+        GROW_BUFFER(codec_info_duration, nb_streams, ic->nb_streams);  \
> >+    }                                                                  \
> 
> I suggest to define a struct per stream to simplify the code.

I thought about this too... And then I discarded the idea. I don't
remember exactly why, but I guess I was just too lazy to change all
usage of those vars...
Anyway, I did it now. And it indeed looks a bit cleaner.
I split this into 2 patches. First one moves those vars into a struct,
and second one replace MAX_STREAMS usage by dynamic allocation.

Aurel
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