05.06.2013 14:39, Andrey Utkin пишет:
2013/6/5 Андрей <[email protected]>:
I use to compile the 32-bit version of ffmpeg visual studio 2012. I used the
latter for now build from 5/29/13.
This is my test code that reproduces the problem:
avcodec_register_all();
int width = 764, height = 480;
int got_output;
AVFrame *frame;
AVPacket pkt;
AVCodec *codec;
AVCodecContext *c = NULL;
while(1)
{
frame = avcodec_alloc_frame();
if (!frame) {
fprintf(stderr, "Could not allocate video frame\n");
return -1;
}
frame->format = AV_PIX_FMT_YUV420P;
frame->width = width;
frame->height = height;
/* the image can be allocated by any means and av_image_alloc() is
* just the most convenient way if av_malloc() is to be used */
int ret = av_image_alloc(frame->data, frame->linesize, width,
height,
AV_PIX_FMT_YUV420P, 1);
if (ret < 0) {
fprintf(stderr, "Could not allocate raw picture buffer\n");
av_freep(&frame->data[0]);
avcodec_free_frame(&frame);
return -1;
}
/* find the mpeg4 video encoder */
codec = avcodec_find_encoder(AV_CODEC_ID_MPEG4);
if (!codec) {
fprintf(stderr, "Codec not found\n");
return -1;
}
c = avcodec_alloc_context3(codec);
if (!c) {
fprintf(stderr, "Could not allocate video codec context\n");
return -1;
}
/* put sample parameters */
c->profile = FF_PROFILE_MPEG4_SIMPLE;
/* resolution must be a multiple of two */
c->width = width;
c->height = height;
/* frames per second */
c->time_base.den = 25;
c->time_base.num = 1;
c->gop_size = 25; /* emit one intra frame every 25 frames */
c->pix_fmt = AV_PIX_FMT_YUV420P;
c->qmax = 4;
c->qmin = 4;
/* open it */
if (avcodec_open2(c, codec, NULL) < 0) {
fprintf(stderr, "Could not open codec\n");
avcodec_close(c);
You shouldn't avcodec_close() here. I think this can cause a problem.
av_free(c);
return -1;
}
for(int k = 0; k < 30; k++)
{
av_init_packet(&pkt);
pkt.data = NULL; // packet data will be allocated by the
encoder
pkt.size = 0;
frame->pts = c->frame_number;
/* encode the image */
if (avcodec_encode_video2(c, &pkt, frame, &got_output) < 0) {
fprintf(stderr, "Error encoding frame\n");
return -1;
}
if (got_output) {
av_free_packet(&pkt);
}
}
if(c)
{
avcodec_close(c);
av_free(c);
Can't say for sure, but av_free() seems redundant.
}
if(frame)
{
av_freep(&frame->data[0]);
avcodec_free_frame(&frame);
Maybe there also something is redundant.
}
}
When you call function avcodec_close () throws an exception. Such an error
is detected on the MPEG4 codec with a frame width in the range 754-767 at an
altitude of 480. Perhaps at other resolutions, too. Help solve the problem.
...sorry for bad english
You have more than one call to avcodec_close(), do you know, which one
is executed?
Your code snippet should be easily compiled on linux, there you can
use valgrind memcheck tool, which makes debugging easy.
Also i suggest you to re-read avcodec.h and avformat.h for
explanations on how to release context objects correclty, some places
in your code are suspicious for me.
--
Andrey Utkin
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Ok, for now I'm using video_encode_example from decoding_encoding.c example:
AVCodec *codec;
AVCodecContext *c = NULL;
int i, ret, x, y, got_output;
AVFrame *frame;
AVPacket pkt;
/* register all the codecs */
avcodec_register_all();
/* find the mpeg1 video encoder */
codec = avcodec_find_encoder(AV_CODEC_ID_MPEG4);
if (!codec) {
fprintf(stderr, "Codec not found\n");
exit(1);
}
c = avcodec_alloc_context3(codec);
if (!c) {
fprintf(stderr, "Could not allocate video codec context\n");
exit(1);
}
/* put sample parameters */
c->bit_rate = 400000;
/* resolution must be a multiple of two */
c->width = 764;
c->height = 480;
/* frames per second */
c->time_base.den = 25;
c->time_base.num = 1;
c->gop_size = 10; /* emit one intra frame every ten frames */
c->max_b_frames = 1;
c->pix_fmt = AV_PIX_FMT_YUV420P;
/* open it */
if (avcodec_open2(c, codec, NULL) < 0) {
fprintf(stderr, "Could not open codec\n");
exit(1);
}
frame = avcodec_alloc_frame();
if (!frame) {
fprintf(stderr, "Could not allocate video frame\n");
exit(1);
}
frame->format = c->pix_fmt;
frame->width = c->width;
frame->height = c->height;
/* the image can be allocated by any means and av_image_alloc() is
* just the most convenient way if av_malloc() is to be used */
ret = av_image_alloc(frame->data, frame->linesize, c->width, c->height,
c->pix_fmt, 32);
if (ret < 0) {
fprintf(stderr, "Could not allocate raw picture buffer\n");
exit(1);
}
/* encode 1 second of video */
for(i=0;i<25;i++) {
av_init_packet(&pkt);
pkt.data = NULL; // packet data will be allocated by the encoder
pkt.size = 0;
fflush(stdout);
/* prepare a dummy image */
/* Y */
for(y=0;y<c->height;y++) {
for(x=0;x<c->width;x++) {
frame->data[0][y * frame->linesize[0] + x] = x + y + i * 3;
}
}
/* Cb and Cr */
for(y=0;y<c->height/2;y++) {
for(x=0;x<c->width/2;x++) {
frame->data[1][y * frame->linesize[1] + x] = 128 + y +
i * 2;
frame->data[2][y * frame->linesize[2] + x] = 64 + x + i
* 5;
}
}
frame->pts = i;
/* encode the image */
ret = avcodec_encode_video2(c, &pkt, frame, &got_output);
if (ret < 0) {
fprintf(stderr, "Error encoding frame\n");
exit(1);
}
if (got_output) {
av_free_packet(&pkt);
}
}
avcodec_close(c);
av_free(c);
av_freep(&frame->data[0]);
avcodec_free_frame(&frame);
The problem is that the context is not released correctly when the
resolution is 764x480 and some other resolutions. If you use a different
codec instead of MPEG4, such as H264, no error occurs if any resolution.
I use the assembly under windows and unfortunately I do not have the
possibility to compile the example under Linux to pinpoint the cause of
the fall.
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