How to release resources from ffmpeg - ffmpeg

Question

I have built a class that reads avi file and displays it.
This is the defination for the class.
typedef struct {
AVFormatContext *fmt_ctx;
int stream_idx;
AVStream *video_stream;
AVCodecContext *codec_ctx;
AVCodec *decoder;
AVPacket *packet;
AVFrame *av_frame;
AVFrame *gl_frame;
struct SwsContext *conv_ctx;
unsigned int frame_tex;
}AppData;
class ClipPlayer{
private:
AppData data;
std::vector< AVFrame* > cache;
public:
ClipPlayer();
ClipPlayer(const ClipPlayer& player);
ClipPlayer& operator=(const ClipPlayer& player);
~ClipPlayer();
void initializeAppData();
void clearAppData();
bool readFrame();
bool initReadFrame();
void playCache();
void init();
void draw();
void reset();
}
In the init function the AVI file is read and the frames are saved in memory.
void init()
{
initializeAppData();
// open video
if (avformat_open_input(&data.fmt_ctx, stdstrPathOfVideo.c_str(), NULL, NULL) < 0) {
clearAppData();
return;
}
// find stream info
if (avformat_find_stream_info(data.fmt_ctx, NULL) < 0) {
clearAppData();
return;
}
// find the video stream
for (unsigned int i = 0; i < data.fmt_ctx->nb_streams; ++i)
{
if (data.fmt_ctx->streams[i]->codec->codec_type == AVMEDIA_TYPE_VIDEO)
{
data.stream_idx = i;
break;
}
}
if (data.stream_idx == -1)
{
clearAppData();
return;
}
data.video_stream = data.fmt_ctx->streams[data.stream_idx];
data.codec_ctx = data.video_stream->codec;
// find the decoder
data.decoder = avcodec_find_decoder(data.codec_ctx->codec_id);
if (data.decoder == NULL)
{
clearAppData();
return;
}
// open the decoder
if (avcodec_open2(data.codec_ctx, data.decoder, NULL) < 0)
{
clearAppData();
return;
}
// allocate the video frames
data.av_frame = av_frame_alloc();
data.gl_frame = av_frame_alloc();
int size = avpicture_get_size(AV_PIX_FMT_RGBA, data.codec_ctx->width,
data.codec_ctx->height);
uint8_t *internal_buffer = (uint8_t *)av_malloc(size * sizeof(uint8_t));
avpicture_fill((AVPicture *)data.gl_frame, internal_buffer, AV_PIX_FMT_RGBA,
data.codec_ctx->width, data.codec_ctx->height);
data.packet = (AVPacket *)av_malloc(sizeof(AVPacket));
}
/////////////////////////////////////////////////////////////
bool ClipPlayer::initReadFrame()
{
do {
glBindTexture(GL_TEXTURE_2D, data.frame_tex);
int error = av_read_frame(data.fmt_ctx, data.packet);
if (error)
{
av_free_packet(data.packet);
return false;
}
if (data.packet->stream_index == data.stream_idx)
{
int frame_finished = 0;
if (avcodec_decode_video2(data.codec_ctx, data.av_frame, &frame_finished,
data.packet) < 0) {
av_free_packet(data.packet);
return false;
}
if (frame_finished)
{
if (!data.conv_ctx)
{
data.conv_ctx = sws_getContext(data.codec_ctx->width,
data.codec_ctx->height, data.codec_ctx->pix_fmt,
data.codec_ctx->width, data.codec_ctx->height, AV_PIX_FMT_RGBA,
SWS_BICUBIC, NULL, NULL, NULL);
}
sws_scale(data.conv_ctx, data.av_frame->data, data.av_frame->linesize, 0,
data.codec_ctx->height, data.gl_frame->data, data.gl_frame->linesize);
glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, data.codec_ctx->width,
data.codec_ctx->height, GL_RGBA, GL_UNSIGNED_BYTE,
data.gl_frame->data[0]);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
AVFrame *cachedValue = av_frame_alloc();
cachedValue->format = data.av_frame->format;
cachedValue->width = data.av_frame->width;
cachedValue->height = data.av_frame->height;
cachedValue->channels = data.av_frame->channels;
cachedValue->channel_layout = data.av_frame->channel_layout;
cachedValue->nb_samples = data.av_frame->nb_samples;
av_frame_get_buffer(cachedValue, 32);
av_frame_copy(cachedValue, data.av_frame);
av_frame_copy_props(cachedValue, data.av_frame);
cache.push_back((cachedValue));
}
}
} while (data.packet->stream_index != data.stream_idx);
////////////////////////////////////////////////////////////////////
In the play cache function the frames are displayed
void ClipPlayer::playCache()
{
glActiveTexture(GL_TEXTURE0);
sws_scale(data.conv_ctx, cache[loop]->data, cache[loop]->linesize, 0,
data.codec_ctx->height, data.gl_frame->data, data.gl_frame->linesize);
glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, data.codec_ctx->width,
data.codec_ctx->height, GL_RGBA, GL_UNSIGNED_BYTE,data.gl_frame->data[0]);
glBindTexture(GL_TEXTURE_2D, data.frame_tex);
}
In the destructor i try to free the memory
~ClipPlayer()
{
for (auto &frame : cache)
{
av_freep(frame);
}
}
I am not very proficient in using FFmpeg , my question is that have i freed the memory properly.

Answer 1

Your code two apparent problem.
You should use av_frame_unref() instead of av_freep() for AVFrames.
avpicture_fill is deprecated long ago. IF your ffmpeg installation is old. Update it. Otherwise use av_image_fill_arrays() instead.
You can refer up to date API documentation here: http://www.ffmpeg.org/doxygen/trunk/index.html
Hope that helps.