[FFmpeg-cvslog] alsa: limit buffer_size to 32768 frames.

[Justin Ruggles]

ffmpeg | branch: release/0.8 | Justin Ruggles <justin.ruggles at gmail.com> | Wed Jun 22 16:38:20 2011 -0400| [0c039db4d8aa0928d9b7466c635247e6439df015] | committer: Reinhard Tartler

alsa: limit buffer_size to 32768 frames.

In testing, the file output plugin gave a max buffer size of about 20 million
frames, which is way more than what is really needed and causes a memory
allocation error on my system.
(cherry picked from commit e35c674d13a7f180412cfe058530a2e7f1d49a90)

Signed-off-by: Anton Khirnov <anton at khirnov.net>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=0c039db4d8aa0928d9b7466c635247e6439df015
---

 libavdevice/alsa-audio-common.c |    1 +
 libavdevice/alsa-audio.h        |    2 ++
 2 files changed, 3 insertions(+), 0 deletions(-)

diff --git a/libavdevice/alsa-audio-common.c b/libavdevice/alsa-audio-common.c
index 4c7c881..825fcb1 100644
--- a/libavdevice/alsa-audio-common.c
+++ b/libavdevice/alsa-audio-common.c
@@ -137,6 +137,7 @@ av_cold int ff_alsa_open(AVFormatContext *ctx, snd_pcm_stream_t mode,
     }
 
     snd_pcm_hw_params_get_buffer_size_max(hw_params, &buffer_size);
+    buffer_size = FFMIN(buffer_size, ALSA_BUFFER_SIZE_MAX);
     /* TODO: maybe use ctx->max_picture_buffer somehow */
     res = snd_pcm_hw_params_set_buffer_size_near(h, hw_params, &buffer_size);
     if (res < 0) {
diff --git a/libavdevice/alsa-audio.h b/libavdevice/alsa-audio.h
index 32c0742..c8c6ea4 100644
--- a/libavdevice/alsa-audio.h
+++ b/libavdevice/alsa-audio.h
@@ -40,6 +40,8 @@
         other formats */
 #define DEFAULT_CODEC_ID AV_NE(CODEC_ID_PCM_S16BE, CODEC_ID_PCM_S16LE)
 
+#define ALSA_BUFFER_SIZE_MAX 32768
+
 typedef struct {
     AVClass *class;
     snd_pcm_t *h;