On Mon, Jun 22, 2015 at 10:50 AM, Ludmila Glinskih <lglins...@gmail.com> wrote:
> +static int video_decode_example(const char *input_filename)
> +{
> + AVCodec *codec = NULL;
> + AVCodecContext *origin_ctx = NULL, *ctx= NULL;
> + AVFrame *fr = NULL;
> + uint8_t *byte_buffer = NULL;
> + AVPacket pkt;
> + AVFormatContext *fmt_ctx = NULL;
> + int number_of_written_bytes;
> + int video_stream;
> + int get_frame = 0;
> + int byte_buffer_size;
> + int i = 0;
> +
> +
> + if (avformat_open_input(&fmt_ctx, input_filename, NULL, NULL) < 0) {
> + fprintf(stderr, "Could not open source file %s\n", input_filename);
> + exit(1);
> + }
> +
> + if (avformat_find_stream_info(fmt_ctx, NULL) < 0) {
> + fprintf(stderr, "Could not find stream information\n");
> + exit(1);
> + }
> +
> + video_stream = -1;
> + for (i = 0; i < fmt_ctx->nb_streams; i++) {
> + if (fmt_ctx->streams[i]->codec->codec_type == AVMEDIA_TYPE_VIDEO) {
> + video_stream = i;
> + break;
> + }
> + }
> +
> + origin_ctx = fmt_ctx->streams[video_stream]->codec;
> +
> + codec = avcodec_find_decoder(origin_ctx->codec_id);
> + if (codec == NULL) {
> + return -1;
> + }
> + ctx = avcodec_alloc_context3(codec);
> + if (ctx == NULL) {
> + return -1;
> + }
> +
> + if (avcodec_copy_context(ctx, origin_ctx)) {
> + return -1;
> + }
> +
> + if (avcodec_open2(ctx, codec, NULL) < 0) {
> + return -1;
> + }
> +
> + fr = av_frame_alloc();
> + if (fr == NULL) {
> + return -1;
> + }
> +
> + byte_buffer_size = av_image_get_buffer_size(ctx->pix_fmt, ctx->width,
> ctx->height, 16);
> + byte_buffer = av_malloc(byte_buffer_size);
> +
> + printf("#tb %d: %d/%d\n", video_stream,
> fmt_ctx->streams[video_stream]->time_base.num,
> fmt_ctx->streams[video_stream]->time_base.den);
> + i = 0;
> + av_init_packet(&pkt);
> + while (av_read_frame(fmt_ctx, &pkt) >= 0) {
> + if (pkt.stream_index == video_stream) {
> + get_frame = 0;
> + if (pkt.pts == AV_NOPTS_VALUE)
> + pkt.pts = pkt.dts = i;
> + avcodec_decode_video2(ctx, fr, &get_frame, &pkt);
> + if (get_frame) {
> + number_of_written_bytes =
> av_image_copy_to_buffer(byte_buffer, byte_buffer_size,
> + (const uint8_t* const *)fr->data,
> (const int*) fr->linesize,
> + ctx->pix_fmt, ctx->width,
> ctx->height, 1);
> + printf("%d, %10"PRId64", %10"PRId64", %8d, %8d,
> 0x%08"PRIx32"\n", video_stream,
> + fr->pkt_pts, fr->pkt_dts, fr->pkt_duration,
> + number_of_written_bytes, av_adler32_update(0, (const
> uint8_t*)byte_buffer, number_of_written_bytes));
> + }
> + av_free_packet(&pkt);
> + av_init_packet(&pkt);
> + }
> + i++;
> + }
> + pkt.data = NULL;
> + pkt.size = 0;
> + if (pkt.pts == AV_NOPTS_VALUE)
> + pkt.pts = pkt.dts = i;
> + int flag = 0;
> + while (!flag) {
> + if (pkt.stream_index != video_stream)
> + break;
> + get_frame = 0;
> + if (avcodec_decode_video2(ctx, fr, &get_frame, &pkt) < 0 ||
> get_frame == 0)
> + flag = 1;
> + if (get_frame) {
> + number_of_written_bytes = av_image_copy_to_buffer(byte_buffer,
> byte_buffer_size,
> + (const uint8_t* const *)fr->data, (const
> int*) fr->linesize,
> + ctx->pix_fmt, ctx->width, ctx->height,
> 1);
> + printf("%d, %10"PRId64", %10"PRId64", %8d, %8d,
> 0x%08"PRIx32"\n", video_stream,
> + fr->pkt_pts, fr->pkt_dts, fr->pkt_duration,
> + number_of_written_bytes, av_adler32_update(0, (const
> uint8_t*)byte_buffer, number_of_written_bytes));
> + }
> + i++;
> + }
> + av_free_packet(&pkt);
> + av_frame_free(&fr);
> + avcodec_close(ctx);
> + avformat_close_input(&fmt_ctx);
> + avcodec_free_context(&ctx);
> + av_freep(&byte_buffer);
> + return 0;
> +}
> +
> +int main(int argc, char **argv)
> +{
> + av_register_all();
> + video_decode_example(argv[1]);
> + return 0;
> +}
video_decode_example can return -1 on error, and this is lost, so
you'd better do "return video_decode_example(argv[1]);" to return the
value to the caller. Also sometimes you exit(1) and sometimes you
return -1, maybe you could go with only one of them.
--
Vittorio
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