Hello,
I'm using the following code to convert a frame from a mp4 video to
a PNG image. Whenever I execute the my function (posted below) I receive
the following error message:
[swscaler @ 0x7fe4fb818600] bad src image pointers
This error occurs at the following line in my code:
sws_scale(scalerCtx,
(const uint8_t * const *) pFrame->data,
pFrame->linesize,
0,
src_height,
pFrameRGB->data,
pFrameRGB->linesize);
I've tracked down the error message in the FFmpeg source code but I'm
unsure how to solve this problem. Can anyone help? Thanks in advance!
void convert_image(AVCodecContext *pCodecCtx, AVFrame *pFrame, AVPacket
*avpkt, int *got_packet_ptr) {
AVCodecContext *codecCtx;
AVCodec *codec;
*got_packet_ptr = 0;
codec = avcodec_find_encoder(TARGET_IMAGE_CODEC);
if (!codec) {
printf("avcodec_find_decoder() failed to find decoder\n");
goto fail;
}
codecCtx = avcodec_alloc_context3(codec);
if (!codecCtx) {
printf("avcodec_alloc_context3 failed\n");
goto fail;
}
codecCtx->bit_rate = pCodecCtx->bit_rate;
codecCtx->width = pCodecCtx->width;
codecCtx->height = pCodecCtx->height;
codecCtx->pix_fmt = TARGET_IMAGE_FORMAT;
codecCtx->codec_type = AVMEDIA_TYPE_VIDEO;
codecCtx->time_base.num = pCodecCtx->time_base.num;
codecCtx->time_base.den = pCodecCtx->time_base.den;
if (!codec || avcodec_open2(codecCtx, codec, NULL) < 0) {
printf("avcodec_open2() failed\n");
goto fail;
}
int src_width = pCodecCtx->width;
int src_height = pCodecCtx->height;
enum PixelFormat src_pixfmt = pCodecCtx->pix_fmt;
int dst_width = pCodecCtx->width;
int dst_height = pCodecCtx->height;
struct SwsContext *scalerCtx;
scalerCtx = sws_getContext(src_width,
src_height,
src_pixfmt,
dst_width,
dst_height,
TARGET_IMAGE_FORMAT,
SWS_BILINEAR,
NULL, NULL, NULL);
if (!scalerCtx) {
printf("sws_getContext() failed\n");
goto fail;
}
AVFrame *pFrameRGB = avcodec_alloc_frame();
if (!pFrameRGB) {
goto fail;
}
int numBytes = avpicture_get_size(TARGET_IMAGE_FORMAT, src_width,
src_height);
uint8_t *buffer = (uint8_t *) av_malloc(numBytes * sizeof(uint8_t));
if (avpicture_fill((AVPicture *) pFrameRGB,
buffer,
TARGET_IMAGE_FORMAT,
src_width,
src_height) < 0) {
printf("avpicture_fill() failed\n");
goto fail;
}
sws_scale(scalerCtx,
(const uint8_t * const *) pFrame->data,
pFrame->linesize,
0,
src_height,
pFrameRGB->data,
pFrameRGB->linesize);
int ret = avcodec_encode_video2(codecCtx, avpkt, pFrameRGB,
got_packet_ptr);
if (ret < 0) {
*got_packet_ptr = 0;
}
// TODO is this right?
fail:
if (codecCtx) {
avcodec_close(codecCtx);
}
if (scalerCtx) {
sws_freeContext(scalerCtx);
}
if (ret < 0 || !*got_packet_ptr) {
av_free_packet(avpkt);
}
}
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