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ffmpeg: accept "chapters" as forced key frames.

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Allow to force a key frame at the beginning of each chapter.
This commit is contained in:
Nicolas George 2013-01-02 19:08:08 +01:00
parent 9381521968
commit beb5d8f07d
2 changed files with 54 additions and 8 deletions
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10
doc/ffmpeg.texi
View File

@ -555,9 +555,17 @@ Deprecated see -bsf
@item -force_key_frames[:@var{stream_specifier}] @var{time}[,@var{time}...] (@emph{output,per-stream})
Force key frames at the specified timestamps, more precisely at the first
frames after each specified time.
If one of the times is "@code{chapters}[@var{delta}]", it is expanded into
the time of the beginning of all chapters in the file, shifted by
@var{delta}, expressed as a time in seconds.
This option can be useful to ensure that a seek point is present at a
chapter mark or any other designated place in the output file.
The timestamps must be specified in ascending order.
For example, to insert a key frame at 5 minutes, plus key frames 0.1 second
before the beginning of every chapter:
@example
-force_key_frames 0:05:00,chapters-0.1
@end example
@item -copyinkf[:@var{stream_specifier}] (@emph{output,per-stream})
When doing stream copy, copy also non-key frames found at the

52
ffmpeg.c
View File

@ -1931,19 +1931,25 @@ static InputStream *get_input_stream(OutputStream *ost)
return NULL;
}
static int compare_int64(const void *a, const void *b)
{
int64_t va = *(int64_t *)a, vb = *(int64_t *)b;
return va < vb ? -1 : va > vb ? +1 : 0;
}
static void parse_forced_key_frames(char *kf, OutputStream *ost,
AVCodecContext *avctx)
{
char *p;
int n = 1, i;
int64_t t;
int n = 1, i, size, index = 0;
int64_t t, *pts;
for (p = kf; *p; p++)
if (*p == ',')
n++;
ost->forced_kf_count = n;
ost->forced_kf_pts = av_malloc(sizeof(*ost->forced_kf_pts) * n);
if (!ost->forced_kf_pts) {
size = n;
pts = av_malloc(sizeof(*pts) * size);
if (!pts) {
av_log(NULL, AV_LOG_FATAL, "Could not allocate forced key frames array.\n");
exit(1);
}
@ -1955,11 +1961,43 @@ static void parse_forced_key_frames(char *kf, OutputStream *ost,
if (next)
*next++ = 0;
t = parse_time_or_die("force_key_frames", p, 1);
ost->forced_kf_pts[i] = av_rescale_q(t, AV_TIME_BASE_Q, avctx->time_base);
if (!memcmp(p, "chapters", 8)) {
AVFormatContext *avf = output_files[ost->file_index]->ctx;
int j;
if (avf->nb_chapters > INT_MAX - size ||
!(pts = av_realloc_f(pts, size += avf->nb_chapters - 1,
sizeof(*pts)))) {
av_log(NULL, AV_LOG_FATAL,
"Could not allocate forced key frames array.\n");
exit(1);
}
t = p[8] ? parse_time_or_die("force_key_frames", p + 8, 1) : 0;
t = av_rescale_q(t, AV_TIME_BASE_Q, avctx->time_base);
for (j = 0; j < avf->nb_chapters; j++) {
AVChapter *c = avf->chapters[j];
av_assert1(index < size);
pts[index++] = av_rescale_q(c->start, c->time_base,
avctx->time_base) + t;
}
} else {
t = parse_time_or_die("force_key_frames", p, 1);
av_assert1(index < size);
pts[index++] = av_rescale_q(t, AV_TIME_BASE_Q, avctx->time_base);
}
p = next;
}
av_assert0(index == size);
qsort(pts, size, sizeof(*pts), compare_int64);
ost->forced_kf_count = size;
ost->forced_kf_pts = pts;
}
static void report_new_stream(int input_index, AVPacket *pkt)