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authorMicah F. Galizia <micahgalizia@gmail.com>2010-03-14 22:40:16 +0000
committerStefano Sabatini <stefano.sabatini-lala@poste.it>2010-03-14 22:40:16 +0000
commiteadd495d06b5c553f6026fe905dd0b3bc23fe35b (patch)
treea0ce6874ea498bf0f58017f3780e0c1b279017bc /libavformat/utils.c
parent1e470fadcbe08cd3397b7658784b7fb7fcb5ceeb (diff)
Move the probe loop from av_open_input_file() into its own method
av_probe_input_buffer() so that it can be reused. Here are a few differences to the original way things were probed: - maximum probe buffer size can be specified as a parameter. - offset within the stream to probe from can be specified as a parameter. - instead of seeking back to the start each time a probe fails, stream data is appended to the reallocated buffer. This lowers the amount of data read from the stream (there is no repetition) and results in fewer closed and reopened streams (when seeking fails). New attempt after r22296, which was revert in r22315 due to a FATE failure. See the thread: Subject: [FFmpeg-devel] [PATCH] Move av_open_input_file probe loop to its own method Date: 2010-03-05 03:23:57 GMT Patch by Micah F. Galizia printf("%s%s@%s.%s", "micah", "galizia", "gmail", "com"). Originally committed as revision 22532 to svn://svn.ffmpeg.org/ffmpeg/trunk
Diffstat (limited to 'libavformat/utils.c')
-rw-r--r--libavformat/utils.c97
1 files changed, 66 insertions, 31 deletions
diff --git a/libavformat/utils.c b/libavformat/utils.c
index b2ecf13bb1..f6cbbb4a93 100644
--- a/libavformat/utils.c
+++ b/libavformat/utils.c
@@ -458,12 +458,75 @@ int av_open_input_stream(AVFormatContext **ic_ptr,
#define PROBE_BUF_MIN 2048
#define PROBE_BUF_MAX (1<<20)
+int ff_probe_input_buffer(ByteIOContext **pb, AVInputFormat **fmt,
+ const char *filename, void *logctx,
+ unsigned int offset, unsigned int max_probe_size)
+{
+ AVProbeData pd = { filename ? filename : "", NULL, -offset };
+ unsigned char *buf = NULL;
+ int ret = 0, probe_size;
+
+ if (!max_probe_size) {
+ max_probe_size = PROBE_BUF_MAX;
+ } else if (max_probe_size > PROBE_BUF_MAX) {
+ max_probe_size = PROBE_BUF_MAX;
+ } else if (max_probe_size < PROBE_BUF_MIN) {
+ return AVERROR(EINVAL);
+ }
+
+ if (offset >= max_probe_size) {
+ return AVERROR(EINVAL);
+ }
+
+ for(probe_size= PROBE_BUF_MIN; probe_size<=max_probe_size && !*fmt && ret >= 0; probe_size<<=1){
+ int ret, score = probe_size < max_probe_size ? AVPROBE_SCORE_MAX/4 : 0;
+ int buf_offset = (probe_size == PROBE_BUF_MIN) ? 0 : probe_size>>1;
+
+ if (probe_size < offset) {
+ continue;
+ }
+
+ /* read probe data */
+ buf = av_realloc(buf, probe_size + AVPROBE_PADDING_SIZE);
+ if ((ret = get_buffer(*pb, buf + buf_offset, probe_size - buf_offset)) < 0) {
+ /* fail if error was not end of file, otherwise, lower score */
+ if (ret != AVERROR_EOF) {
+ av_free(buf);
+ return ret;
+ }
+ score = 0;
+ }
+ pd.buf_size += ret;
+ pd.buf = &buf[offset];
+
+ memset(pd.buf + pd.buf_size, 0, AVPROBE_PADDING_SIZE);
+
+ /* guess file format */
+ *fmt = av_probe_input_format2(&pd, 1, &score);
+ if(*fmt){
+ if(score <= AVPROBE_SCORE_MAX/4){ //this can only be true in the last iteration
+ av_log(logctx, AV_LOG_WARNING, "Format detected only with low score of %d, misdetection possible!\n", score);
+ }else
+ av_log(logctx, AV_LOG_DEBUG, "Probed with size=%d and score=%d\n", probe_size, score);
+ }
+ }
+
+ av_free(buf);
+ if (url_fseek(*pb, 0, SEEK_SET) < 0) {
+ url_fclose(*pb);
+ if (url_fopen(pb, filename, URL_RDONLY) < 0)
+ return AVERROR(EIO);
+ }
+
+ return 0;
+}
+
int av_open_input_file(AVFormatContext **ic_ptr, const char *filename,
AVInputFormat *fmt,
int buf_size,
AVFormatParameters *ap)
{
- int err, probe_size;
+ int err;
AVProbeData probe_data, *pd = &probe_data;
ByteIOContext *pb = NULL;
void *logctx= ap && ap->prealloced_context ? *ic_ptr : NULL;
@@ -489,37 +552,9 @@ int av_open_input_file(AVFormatContext **ic_ptr, const char *filename,
if (buf_size > 0) {
url_setbufsize(pb, buf_size);
}
-
- for(probe_size= PROBE_BUF_MIN; probe_size<=PROBE_BUF_MAX && !fmt; probe_size<<=1){
- int score= probe_size < PROBE_BUF_MAX ? AVPROBE_SCORE_MAX/4 : 0;
- /* read probe data */
- pd->buf= av_realloc(pd->buf, probe_size + AVPROBE_PADDING_SIZE);
- pd->buf_size = get_buffer(pb, pd->buf, probe_size);
-
- if ((int)pd->buf_size < 0) {
- err = pd->buf_size;
- goto fail;
- }
-
- memset(pd->buf+pd->buf_size, 0, AVPROBE_PADDING_SIZE);
- if (url_fseek(pb, 0, SEEK_SET) < 0) {
- url_fclose(pb);
- if (url_fopen(&pb, filename, URL_RDONLY) < 0) {
- pb = NULL;
- err = AVERROR(EIO);
- goto fail;
- }
- }
- /* guess file format */
- fmt = av_probe_input_format2(pd, 1, &score);
- if(fmt){
- if(score <= AVPROBE_SCORE_MAX/4){ //this can only be true in the last iteration
- av_log(logctx, AV_LOG_WARNING, "Format detected only with low score of %d, misdetection possible!\n", score);
- }else
- av_log(logctx, AV_LOG_DEBUG, "Probed with size=%d and score=%d\n", probe_size, score);
- }
+ if ((err = ff_probe_input_buffer(&pb, &fmt, filename, logctx, 0, 0)) < 0) {
+ goto fail;
}
- av_freep(&pd->buf);
}
/* if still no format found, error */