[FFmpeg-cvslog] output example: use a struct to bundle the video stream variables together
Anton Khirnov
git at videolan.org
Thu Jun 26 22:12:22 CEST 2014
ffmpeg | branch: master | Anton Khirnov <anton at khirnov.net> | Sat Jun 21 17:17:40 2014 +0200| [294daf71a7a1303b5ddd3cbefebed3b732d610f3] | committer: Anton Khirnov
output example: use a struct to bundle the video stream variables together
> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=294daf71a7a1303b5ddd3cbefebed3b732d610f3
---
doc/examples/output.c | 93 ++++++++++++++++++++++++++-----------------------
1 file changed, 50 insertions(+), 43 deletions(-)
diff --git a/doc/examples/output.c b/doc/examples/output.c
index 52b01d0..620be15 100644
--- a/doc/examples/output.c
+++ b/doc/examples/output.c
@@ -46,6 +46,14 @@
static int sws_flags = SWS_BICUBIC;
+// a wrapper around a single output AVStream
+typedef struct OutputStream {
+ AVStream *st;
+
+ AVFrame *frame;
+ AVFrame *tmp_frame;
+} OutputStream;
+
/**************************************************************/
/* audio output */
@@ -176,14 +184,13 @@ static void close_audio(AVFormatContext *oc, AVStream *st)
/**************************************************************/
/* video output */
-static AVFrame *picture, *tmp_picture;
static int frame_count;
/* Add a video output stream. */
-static AVStream *add_video_stream(AVFormatContext *oc, enum AVCodecID codec_id)
+static void add_video_stream(OutputStream *ost, AVFormatContext *oc,
+ enum AVCodecID codec_id)
{
AVCodecContext *c;
- AVStream *st;
AVCodec *codec;
/* find the video encoder */
@@ -193,13 +200,13 @@ static AVStream *add_video_stream(AVFormatContext *oc, enum AVCodecID codec_id)
exit(1);
}
- st = avformat_new_stream(oc, codec);
- if (!st) {
+ ost->st = avformat_new_stream(oc, codec);
+ if (!ost->st) {
fprintf(stderr, "Could not alloc stream\n");
exit(1);
}
- c = st->codec;
+ c = ost->st->codec;
/* Put sample parameters. */
c->bit_rate = 400000;
@@ -227,8 +234,6 @@ static AVStream *add_video_stream(AVFormatContext *oc, enum AVCodecID codec_id)
/* Some formats want stream headers to be separate. */
if (oc->oformat->flags & AVFMT_GLOBALHEADER)
c->flags |= CODEC_FLAG_GLOBAL_HEADER;
-
- return st;
}
static AVFrame *alloc_picture(enum AVPixelFormat pix_fmt, int width, int height)
@@ -254,11 +259,11 @@ static AVFrame *alloc_picture(enum AVPixelFormat pix_fmt, int width, int height)
return picture;
}
-static void open_video(AVFormatContext *oc, AVStream *st)
+static void open_video(AVFormatContext *oc, OutputStream *ost)
{
AVCodecContext *c;
- c = st->codec;
+ c = ost->st->codec;
/* open the codec */
if (avcodec_open2(c, NULL, NULL) < 0) {
@@ -267,8 +272,8 @@ static void open_video(AVFormatContext *oc, AVStream *st)
}
/* Allocate the encoded raw picture. */
- picture = alloc_picture(c->pix_fmt, c->width, c->height);
- if (!picture) {
+ ost->frame = alloc_picture(c->pix_fmt, c->width, c->height);
+ if (!ost->frame) {
fprintf(stderr, "Could not allocate picture\n");
exit(1);
}
@@ -276,10 +281,10 @@ static void open_video(AVFormatContext *oc, AVStream *st)
/* If the output format is not YUV420P, then a temporary YUV420P
* picture is needed too. It is then converted to the required
* output format. */
- tmp_picture = NULL;
+ ost->tmp_frame = NULL;
if (c->pix_fmt != AV_PIX_FMT_YUV420P) {
- tmp_picture = alloc_picture(AV_PIX_FMT_YUV420P, c->width, c->height);
- if (!tmp_picture) {
+ ost->tmp_frame = alloc_picture(AV_PIX_FMT_YUV420P, c->width, c->height);
+ if (!ost->tmp_frame) {
fprintf(stderr, "Could not allocate temporary picture\n");
exit(1);
}
@@ -316,13 +321,13 @@ static void fill_yuv_image(AVFrame *pict, int frame_index,
}
}
-static void write_video_frame(AVFormatContext *oc, AVStream *st)
+static void write_video_frame(AVFormatContext *oc, OutputStream *ost)
{
int ret;
AVCodecContext *c;
static struct SwsContext *img_convert_ctx;
- c = st->codec;
+ c = ost->st->codec;
if (frame_count >= STREAM_NB_FRAMES) {
/* No more frames to compress. The codec has a latency of a few
@@ -344,11 +349,11 @@ static void write_video_frame(AVFormatContext *oc, AVStream *st)
exit(1);
}
}
- fill_yuv_image(tmp_picture, frame_count, c->width, c->height);
- sws_scale(img_convert_ctx, tmp_picture->data, tmp_picture->linesize,
- 0, c->height, picture->data, picture->linesize);
+ fill_yuv_image(ost->tmp_frame, frame_count, c->width, c->height);
+ sws_scale(img_convert_ctx, ost->tmp_frame->data, ost->tmp_frame->linesize,
+ 0, c->height, ost->frame->data, ost->frame->linesize);
} else {
- fill_yuv_image(picture, frame_count, c->width, c->height);
+ fill_yuv_image(ost->frame, frame_count, c->width, c->height);
}
}
@@ -359,8 +364,8 @@ static void write_video_frame(AVFormatContext *oc, AVStream *st)
av_init_packet(&pkt);
pkt.flags |= AV_PKT_FLAG_KEY;
- pkt.stream_index = st->index;
- pkt.data = (uint8_t *)picture;
+ pkt.stream_index = ost->st->index;
+ pkt.data = (uint8_t *)ost->frame;
pkt.size = sizeof(AVPicture);
ret = av_interleaved_write_frame(oc, &pkt);
@@ -370,11 +375,11 @@ static void write_video_frame(AVFormatContext *oc, AVStream *st)
av_init_packet(&pkt);
/* encode the image */
- ret = avcodec_encode_video2(c, &pkt, picture, &got_packet);
+ ret = avcodec_encode_video2(c, &pkt, ost->frame, &got_packet);
/* If size is zero, it means the image was buffered. */
if (!ret && got_packet && pkt.size) {
- av_packet_rescale_ts(&pkt, c->time_base, st->time_base);
- pkt.stream_index = st->index;
+ av_packet_rescale_ts(&pkt, c->time_base, ost->st->time_base);
+ pkt.stream_index = ost->st->index;
/* Write the compressed frame to the media file. */
ret = av_interleaved_write_frame(oc, &pkt);
@@ -389,11 +394,11 @@ static void write_video_frame(AVFormatContext *oc, AVStream *st)
frame_count++;
}
-static void close_video(AVFormatContext *oc, AVStream *st)
+static void close_video(AVFormatContext *oc, OutputStream *ost)
{
- avcodec_close(st->codec);
- av_frame_free(&picture);
- av_frame_free(&tmp_picture);
+ avcodec_close(ost->st->codec);
+ av_frame_free(&ost->frame);
+ av_frame_free(&ost->tmp_frame);
}
/**************************************************************/
@@ -401,11 +406,13 @@ static void close_video(AVFormatContext *oc, AVStream *st)
int main(int argc, char **argv)
{
+ OutputStream video_st;
const char *filename;
AVOutputFormat *fmt;
AVFormatContext *oc;
- AVStream *audio_st, *video_st;
+ AVStream *audio_st;
double audio_pts, video_pts;
+ int have_video = 0;
int i;
/* Initialize libavcodec, and register all codecs and formats. */
@@ -444,10 +451,10 @@ int main(int argc, char **argv)
/* Add the audio and video streams using the default format codecs
* and initialize the codecs. */
- video_st = NULL;
audio_st = NULL;
if (fmt->video_codec != AV_CODEC_ID_NONE) {
- video_st = add_video_stream(oc, fmt->video_codec);
+ add_video_stream(&video_st, oc, fmt->video_codec);
+ have_video = 1;
}
if (fmt->audio_codec != AV_CODEC_ID_NONE) {
audio_st = add_audio_stream(oc, fmt->audio_codec);
@@ -455,8 +462,8 @@ int main(int argc, char **argv)
/* Now that all the parameters are set, we can open the audio and
* video codecs and allocate the necessary encode buffers. */
- if (video_st)
- open_video(oc, video_st);
+ if (have_video)
+ open_video(oc, &video_st);
if (audio_st)
open_audio(oc, audio_st);
@@ -480,21 +487,21 @@ int main(int argc, char **argv)
else
audio_pts = 0.0;
- if (video_st)
- video_pts = (double)video_st->pts.val * video_st->time_base.num /
- video_st->time_base.den;
+ if (have_video)
+ video_pts = (double)video_st.st->pts.val * video_st.st->time_base.num /
+ video_st.st->time_base.den;
else
video_pts = 0.0;
if ((!audio_st || audio_pts >= STREAM_DURATION) &&
- (!video_st || video_pts >= STREAM_DURATION))
+ (!have_video || video_pts >= STREAM_DURATION))
break;
/* write interleaved audio and video frames */
- if (!video_st || (video_st && audio_st && audio_pts < video_pts)) {
+ if (!have_video || (have_video && audio_st && audio_pts < video_pts)) {
write_audio_frame(oc, audio_st);
} else {
- write_video_frame(oc, video_st);
+ write_video_frame(oc, &video_st);
}
}
@@ -505,8 +512,8 @@ int main(int argc, char **argv)
av_write_trailer(oc);
/* Close each codec. */
- if (video_st)
- close_video(oc, video_st);
+ if (have_video)
+ close_video(oc, &video_st);
if (audio_st)
close_audio(oc, audio_st);
More information about the ffmpeg-cvslog
mailing list