From 96aaffd8a0abd4d010adc46ea1748c23846e06d8 Mon Sep 17 00:00:00 2001
From: Anton Khirnov <anton@khirnov.net>
Date: Mon, 22 Apr 2013 16:40:43 +0200
Subject: libav decoder plugin: do not explicitly probe the input format in
 libav_decode()

avformat_open_input() can probe the format itself.
---
 src/decoder/libav_decoder_plugin.c | 97 ++++++++++++++++++++------------------
 1 file changed, 50 insertions(+), 47 deletions(-)

diff --git a/src/decoder/libav_decoder_plugin.c b/src/decoder/libav_decoder_plugin.c
index 026f0c9c..fd404e29 100644
--- a/src/decoder/libav_decoder_plugin.c
+++ b/src/decoder/libav_decoder_plugin.c
@@ -50,7 +50,6 @@ typedef struct LibavDecContext {
     struct input_stream *input;
 
     AVIOContext *io;
-    unsigned char buffer[8192];
 } LibavDecContext;
 
 static GLogLevelFlags
@@ -107,14 +106,22 @@ mpd_libav_stream_seek(void *opaque, int64_t pos, int whence)
     return stream->input->offset;
 }
 
+#define INPUT_BUFFER_SIZE 16384
 static int mpd_libav_stream_open(LibavDecContext *s, struct input_stream *input)
 {
+    uint8_t *buf = av_malloc(INPUT_BUFFER_SIZE);
+
+    if (!buf)
+        return AVERROR(ENOMEM);
+
     s->input = input;
-    s->io = avio_alloc_context(s->buffer, sizeof(s->buffer), 0,
+    s->io = avio_alloc_context(buf, INPUT_BUFFER_SIZE, 0,
                                s, mpd_libav_stream_read, NULL,
                                input->seekable ? mpd_libav_stream_seek : NULL);
-    if (!s->io)
+    if (!s->io) {
+        av_freep(&buf);
         return AVERROR(ENOMEM);
+    }
 
     return 0;
 }
@@ -141,6 +148,7 @@ mpd_libav_open_input(AVFormatContext **ic_ptr,
 static void
 mpd_libav_stream_close(LibavDecContext *stream)
 {
+    av_freep(&stream->io->buffer);
     av_free(stream->io);
 }
 
@@ -288,53 +296,11 @@ libav_sample_format(G_GNUC_UNUSED const AVCodecContext *codec_context)
     }
 }
 
-static AVInputFormat *
-libav_probe(struct decoder *decoder, struct input_stream *is)
-{
-    enum {
-        BUFFER_SIZE = 16384,
-        PADDING = 16,
-    };
-
-    unsigned char *buffer = g_malloc(BUFFER_SIZE);
-    size_t nbytes = decoder_read(decoder, is, buffer, BUFFER_SIZE);
-    if (nbytes <= PADDING ||
-        !input_stream_lock_seek(is, 0, SEEK_SET, NULL)) {
-        g_free(buffer);
-        return NULL;
-    }
-
-    /* some ffmpeg parsers (e.g. ac3_parser.c) read a few bytes
-       beyond the declared buffer limit, which makes valgrind
-       angry; this workaround removes some padding from the buffer
-       size */
-    nbytes -= PADDING;
-
-    AVProbeData avpd = {
-        .buf = buffer,
-        .buf_size = nbytes,
-        .filename = is->uri,
-    };
-
-    AVInputFormat *format = av_probe_input_format(&avpd, true);
-    g_free(buffer);
-
-    return format;
-}
-
 static void libav_decode(struct decoder *decoder, struct input_stream *input)
 {
     LibavDecContext s = { .decoder = decoder };
-    AVInputFormat *input_format;
     int ret;
 
-    input_format = libav_probe(decoder, input);
-    if (input_format == NULL)
-        return;
-
-    g_debug("detected input format '%s' (%s)",
-        input_format->name, input_format->long_name);
-
     s.decoder = decoder;
     ret = mpd_libav_stream_open(&s, input);
     if (ret < 0) {
@@ -344,13 +310,16 @@ static void libav_decode(struct decoder *decoder, struct input_stream *input)
 
     //ffmpeg works with ours "fileops" helper
     AVFormatContext *format_context = NULL;
-    if (mpd_libav_open_input(&format_context, s.io, input->uri,
-                  input_format) != 0) {
+    if (mpd_libav_open_input(&format_context, s.io, input->uri, NULL) != 0) {
         g_warning("Open failed\n");
         mpd_libav_stream_close(&s);
         return;
     }
 
+    g_debug("Successfully opened input stream '%s', detected input format '%s' (%s)",
+            input->uri, format_context->iformat->name, format_context->iformat->long_name);
+
+
     const int find_result =
         avformat_find_stream_info(format_context, NULL);
     if (find_result < 0) {
@@ -452,6 +421,40 @@ static void libav_decode(struct decoder *decoder, struct input_stream *input)
     mpd_libav_stream_close(&s);
 }
 
+static AVInputFormat *libav_probe(struct decoder *decoder, struct input_stream *is)
+{
+    enum {
+        BUFFER_SIZE = 16384,
+        PADDING = 16,
+    };
+
+    unsigned char *buffer = g_malloc(BUFFER_SIZE);
+    size_t nbytes = decoder_read(decoder, is, buffer, BUFFER_SIZE);
+    if (nbytes <= PADDING ||
+        !input_stream_lock_seek(is, 0, SEEK_SET, NULL)) {
+        g_free(buffer);
+        return NULL;
+    }
+
+    /* some ffmpeg parsers (e.g. ac3_parser.c) read a few bytes
+       beyond the declared buffer limit, which makes valgrind
+       angry; this workaround removes some padding from the buffer
+       size */
+    nbytes -= PADDING;
+
+    AVProbeData avpd = {
+        .buf = buffer,
+        .buf_size = nbytes,
+        .filename = is->uri,
+    };
+
+    AVInputFormat *format = av_probe_input_format(&avpd, true);
+    g_free(buffer);
+
+    return format;
+}
+
+
 //no tag reading in ffmpeg, check if playable
 static bool
 libav_scan_stream(struct input_stream *is,
-- 
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